irtplay

The goal of irtplay is to examine the IRT model-data fit on item-level in different ways as well as provide useful functions related to unidimensional item response theory (IRT). In terms of assessing the IRT model-data fit, one of distinguished features of this package is that it gives not only item fit statistics (e.g., chi-square fit statistic (X2; e.g., Bock, 1960; Yen, 1981), likelihood ratio chi-square fit statistic (G2; McKinley & Mills, 1985), infit and outfit statistics (Ames et al., 2015), and S-X2 (Orlando & Thissen, 2000, 2003)) but also graphical displays to look at residuals between between the observed data and model-based predictions (Hambleton, Swaminathan, & Rogers, 1991). More evaluation methods will be included in the future updated version. In addition to the evaluation of IRT model-data fit, there are several useful functions such as estimating proficiency parameters, calibrating item parameters given the fixed effects (aka. ability values), computing asymptotic variance-covariance matrices of item parameter estimates, importing item and/or ability parameters from popular IRT software, generating simulated data, computing the conditional distribution of observed scores using the Lord-Wingersky recursion formula, computing item and test information functions, computing item and test characteristic curve functions, and plotting item and test characteristic curves and item and test information functions.

Installation

You can install the released version of irtplay from CRAN with:

install.packages("irtplay")

The process of evaluating the IRT model-data fit

One way to assess goodness of IRT model-data fit is through an item fit analysis by examining the traditional item fit statistics and looking at the discrepancy between the observed data and model-based predictions. Using irtplay package, the traditional approach of evaluating the IRT model-data fit on item-level can be implemented with three main steps:

  1. Prepare a data set for the IRT item fit analysis (i.e., item meta data, ability estimates, and response data).
  2. Obtain the IRT fit statistics such as the X2, G2, infit, and outfit statistics using the irtfit function.
  3. Based on the results of IRT model fit analysis (i.e., an object of class irtfit) obtained in step 2, draw the IRT residual plots (i.e., raw residual and standardized residual plots) using plot method.

1. Preparing a data set

Before conducting the IRT model fit analysis, it is necessary to prepare a data set. To run the irtfit function, it requires three data sets:

  1. Item meta data including the item ID, number of score categories, IRT models, and item parameters. The item meta data should be in the format of data.frame. You can prepare the data either by using the shape_df function or by creating a data.frame of the item meta data by yourself. If you have output files of item parameter estimates obtained from one of the IRT software such as BILOG-MG 3, PARSCALE 4, flexMIRT, and mirt (R package), the item meta data can be easily obtained using the functions of bring.bilog, bring.parscale, bring.flexmirt, bring.mirt. See the functions of irtfit, test.info, or simdat for more details about the item meta data format.
  2. Examinees’ ability (or proficiency) estimates. It should be in the format of a numeric vector.
  3. Examinees’ response data set for the items. It should be in the format of matrix where a row and column indicate the examinees and the items, respectively. The order of the examinees in the response data set must be exactly the same as that of the examinees’ ability estimates. The order of the items in the response data set must be exactly the same as that of the items in the item meta data.

2. Computing the IRT model-data fit statistics

The irtfit function computes the traditional IRT item fit statistics such as X2, G2, infit, and outfit statistics. To calculate the X2 and G2 statistics, two methods are available to divide the ability scale into several groups. The two methods are “equal.width” for dividing the scale by an equal length of the interval and “equal.freq” for dividing the scale by an equal frequency of examinees. Also, you need to specify the location of ability point at each group (or interval) where the expected probabilities of score categories are calculated from the IRT models. Available locations are “average” for computing the expected probability at the average point of examinees’ ability estimates in each group and “middle” for computing the expected probability at the midpoint of each group.

To use the irtfit function, you need to insert the item meta data in the argument x, the ability estimates in the argument score, and the response data in the argument data. If you want to divide the ability scale into other than ten groups, you need to specify the number of groups in the argument n.width. In addition, if the response data include missing values, you must indicate the missing value in argument missing.

Once the irtfit function has been implemented, you’ll get the fit statistic results and the contingency tables for every item used to calculate the X2 and G2 fit statistics.

3. Drawing the IRT residual plots

Using the saved object of class irtfit, you can use the plot method to evaluate the IRT raw residual and standardized residual plots.

Because the plot method can draw the residual plots for an item at a time, you have to indicate which item will be examined. For this, you can specify an integer value, which is the location of the studied item, in the argument item.loc.

In terms of the raw residual plot, the argument ci.method is used to select a method to estimate the confidence intervals among four methods. Those methods are “wald” for the Wald interval, which is based on the normal approximation (Laplace, 1812), “cp” for Clopper-Pearson interval (Clopper & Pearson, 1934), “wilson” for Wilson score interval (Wilson, 1927), and “wilson.cr” for Wilson score interval with continuity correction (Newcombe, 1998).

Example code for the three main steps described above

The example code below shows how to prepare the data sets and how to conduct the IRT model-data fit analysis:

library(irtplay)

##----------------------------------------------------------------------------
## Step 1: prepare a data set for IRT
## In this example, we use the simulated mixed-item format CAT Data
## But, only items that have item responses more than 1,000 are assessed.

# find the location of items that have more than 1,000 item responses
over1000 <- which(colSums(simCAT_MX$res.dat, na.rm=TRUE) > 1000)

# (1) item meta data
x <- simCAT_MX$item.prm[over1000, ]
dim(x)
#> [1] 113   7
print(x[1:10, ])
#>     id cats model     par.1      par.2 par.3 par.4
#> 2   V2    2  2PLM 0.9152754  1.3843593    NA    NA
#> 3   V3    2  2PLM 1.3454796 -1.2554919    NA    NA
#> 5   V5    2  2PLM 1.0862914  1.7114409    NA    NA
#> 6   V6    2  2PLM 1.1311496 -0.6029080    NA    NA
#> 7   V7    2  2PLM 1.2012407 -0.4721664    NA    NA
#> 8   V8    2  2PLM 1.3244155 -0.6353713    NA    NA
#> 10 V10    2  2PLM 1.2487125  0.1381082    NA    NA
#> 11 V11    2  2PLM 1.4413208  1.2276303    NA    NA
#> 12 V12    2  2PLM 1.2077273 -0.8017795    NA    NA
#> 13 V13    2  2PLM 1.1715456 -1.0803926    NA    NA

# (2) examinee's ability estimates
score <- simCAT_MX$score
length(score)
#> [1] 30000
print(score[1:100])
#>   [1] -0.30311440 -0.67224807 -0.73474583  1.76935738 -0.91017203
#>   [6] -0.28448278  0.81656431 -1.66434615  0.59312008 -0.35182937
#>  [11]  0.23129679 -0.93107524 -0.29971993 -0.32700449 -0.22271651
#>  [16]  1.48912121 -0.92927809  0.43453041 -0.01795450 -0.28365286
#>  [21]  0.01115173 -0.76101441  0.12144273  0.83096135  1.96600585
#>  [26] -0.83510402 -0.40268865 -0.05605526  0.72398446 -0.16026059
#>  [31] -1.09011778  1.22126764 -0.13340360 -1.28230720 -1.05581980
#>  [36]  0.83484173 -0.52136360 -0.66913590 -1.08580804  1.73214834
#>  [41]  0.56950387  0.48016332 -0.03472720 -2.17577824  0.44127032
#>  [46]  0.98913071  1.43861714 -1.08133809 -0.69016072  0.19325797
#>  [51]  0.89998383  1.25383167 -1.09600809  0.50519143 -0.51707395
#>  [56] -0.39474484 -0.45031102  1.85675021  1.50768131  1.06011811
#>  [61] -0.41064797  1.10960278 -0.68853387 -0.59397660 -0.65326436
#>  [66]  0.29147751 -1.86787473  1.04838050 -1.14582092  1.07395234
#>  [71] -0.03828693  0.08445559  0.34582524  0.72300905  0.84448992
#>  [76] -1.86488055  0.77121937  1.66573208  0.10311673 -0.50768866
#>  [81] -1.60992457 -0.23074682  0.16162326  0.26091160  0.60682182
#>  [86]  0.65415304 -0.69923141  1.07545766  0.24060267 -0.93542383
#>  [91]  1.24988766 -0.01826940  1.27403936  0.10985621 -1.19092047
#>  [96]  0.79614598  0.62302338 -0.89455596 -0.03472720  0.20250837

# (3) response data
data <- simCAT_MX$res.dat[, over1000]
dim(data)
#> [1] 30000   113
print(data[1:20, 1:6])
#>       Item.dc.2 Item.dc.3 Item.dc.5 Item.dc.6 Item.dc.7 Item.dc.8
#>  [1,]        NA        NA        NA        NA         0         1
#>  [2,]        NA        NA        NA        NA         0         1
#>  [3,]        NA        NA        NA        NA         1         1
#>  [4,]        NA        NA         0        NA        NA        NA
#>  [5,]        NA         1        NA         0         1         1
#>  [6,]        NA         0        NA         0         1         0
#>  [7,]        NA        NA        NA        NA        NA        NA
#>  [8,]        NA         1        NA         1         1         0
#>  [9,]        NA        NA         0        NA        NA        NA
#> [10,]        NA         0        NA         1         1         0
#> [11,]        NA        NA         0        NA        NA        NA
#> [12,]        NA         1        NA         0         1         1
#> [13,]        NA         0        NA         1         1         0
#> [14,]        NA        NA        NA        NA         1        NA
#> [15,]        NA        NA        NA         1         1         1
#> [16,]         1        NA         0        NA        NA        NA
#> [17,]        NA         0        NA         0         1         0
#> [18,]        NA        NA        NA        NA        NA        NA
#> [19,]        NA         0        NA         0         1         1
#> [20,]        NA        NA        NA        NA        NA        NA

##----------------------------------------------------------------------------
## Step 2: Compute the IRT mode-data fit statistics
# (1) the use of "equal.width"  
fit1 <- irtfit(x=x, score=score, data=data, group.method="equal.width",
               n.width=11, loc.theta="average", range.score=c(-4, 4), D=1, alpha=0.05,
               missing=NA, overSR = 2.5)

# what kinds of internal objects does the results have?
names(fit1)
#> [1] "fit_stat"            "contingency.fitstat" "contingency.plot"   
#> [4] "item_df"             "individual.info"     "ancillary"          
#> [7] "call"

# show the results of the fit statistics
fit1$fit_stat[1:10, ]
#>     id      X2      G2 df.X2 df.G2 crit.value.X2 crit.value.G2 p.value.X2
#> 1   V2  75.070  75.209     8    10         15.51         18.31          0
#> 2   V3 186.880 168.082     8    10         15.51         18.31          0
#> 3   V5 151.329 139.213     8    10         15.51         18.31          0
#> 4   V6 178.409 157.911     8    10         15.51         18.31          0
#> 5   V7 185.438 170.360     9    11         16.92         19.68          0
#> 6   V8 209.653 193.001     8    10         15.51         18.31          0
#> 7  V10 267.444 239.563     9    11         16.92         19.68          0
#> 8  V11 148.896 133.209     7     9         14.07         16.92          0
#> 9  V12 139.295 125.647     9    11         16.92         19.68          0
#> 10 V13 128.422 117.439     9    11         16.92         19.68          0
#>    p.value.G2 outfit infit     N overSR.prop
#> 1           0  1.018 1.016  2018       0.364
#> 2           0  1.124 1.090 11041       0.636
#> 3           0  1.133 1.111  5181       0.727
#> 4           0  1.056 1.045 13599       0.545
#> 5           0  1.078 1.059 18293       0.455
#> 6           0  1.098 1.075 16163       0.636
#> 7           0  1.097 1.073 19702       0.727
#> 8           0  1.129 1.083 13885       0.455
#> 9           0  1.065 1.051 12118       0.636
#> 10          0  1.075 1.059 10719       0.545

# show the contingency tables for the first item (dichotomous)
fit1$contingency.fitstat[[1]]
#>      N freq.0 freq.1 obs.prop.0 obs.prop.1 exp.prob.0 exp.prob.1
#> 1    8      5      3  0.6250000  0.3750000  0.7627914  0.2372086
#> 2   14      8      6  0.5714286  0.4285714  0.7121079  0.2878921
#> 3   60     34     26  0.5666667  0.4333333  0.6708959  0.3291041
#> 4  185     99     86  0.5351351  0.4648649  0.6230537  0.3769463
#> 5  240    115    125  0.4791667  0.5208333  0.5765337  0.4234663
#> 6  349    145    204  0.4154728  0.5845272  0.5301760  0.4698240
#> 7  325    114    211  0.3507692  0.6492308  0.4784096  0.5215904
#> 8  246     82    164  0.3333333  0.6666667  0.4419993  0.5580007
#> 9  377    139    238  0.3687003  0.6312997  0.4086532  0.5913468
#> 10 214     78    136  0.3644860  0.6355140  0.3394647  0.6605353
#>    raw_resid.0 raw_resid.1
#> 1  -0.13779141  0.13779141
#> 2  -0.14067932  0.14067932
#> 3  -0.10422928  0.10422928
#> 4  -0.08791853  0.08791853
#> 5  -0.09736699  0.09736699
#> 6  -0.11470327  0.11470327
#> 7  -0.12764036  0.12764036
#> 8  -0.10866594  0.10866594
#> 9  -0.03995295  0.03995295
#> 10  0.02502128 -0.02502128


# (2) the use of "equal.freq"  
fit2 <- irtfit(x=x, score=score, data=data, group.method="equal.freq",
               n.width=11, loc.theta="average", range.score=c(-4, 4), D=1, alpha=0.05,
               missing=NA)

# show the results of the fit statistics
fit2$fit_stat[1:10, ]
#>     id      X2      G2 df.X2 df.G2 crit.value.X2 crit.value.G2 p.value.X2
#> 1   V2  77.967  78.144     9    11         16.92         19.68          0
#> 2   V3 202.035 181.832     9    11         16.92         19.68          0
#> 3   V5 146.383 135.908     9    11         16.92         19.68          0
#> 4   V6 140.038 133.287     9    11         16.92         19.68          0
#> 5   V7 188.814 177.526     9    11         16.92         19.68          0
#> 6   V8 211.279 196.328     9    11         16.92         19.68          0
#> 7  V10 259.669 239.292     9    11         16.92         19.68          0
#> 8  V11 166.427 150.419     9    11         16.92         19.68          0
#> 9  V12 145.789 134.690     9    11         16.92         19.68          0
#> 10 V13 141.283 132.270     9    11         16.92         19.68          0
#>    p.value.G2 outfit infit     N overSR.prop
#> 1           0  1.018 1.016  2018       0.727
#> 2           0  1.124 1.090 11041       0.636
#> 3           0  1.133 1.111  5181       0.727
#> 4           0  1.056 1.045 13599       0.545
#> 5           0  1.078 1.059 18293       0.455
#> 6           0  1.098 1.075 16163       0.545
#> 7           0  1.097 1.073 19702       0.636
#> 8           0  1.129 1.083 13885       0.636
#> 9           0  1.065 1.051 12118       0.364
#> 10          0  1.075 1.059 10719       0.636

# show the contingency table for the fourth item (polytomous)
fit2$contingency.fitstat[[4]]
#>       N freq.0 freq.1 obs.prop.0 obs.prop.1 exp.prob.0 exp.prob.1
#> 1  1241    967    274  0.7792103  0.2207897  0.8038510  0.1961490
#> 2  1243    879    364  0.7071601  0.2928399  0.7161793  0.2838207
#> 3  1243    784    459  0.6307321  0.3692679  0.6575849  0.3424151
#> 4  1219    747    472  0.6127974  0.3872026  0.6049393  0.3950607
#> 5  1236    705    531  0.5703883  0.4296117  0.5613454  0.4386546
#> 6  1243    677    566  0.5446500  0.4553500  0.5279560  0.4720440
#> 7  1270    662    608  0.5212598  0.4787402  0.4925592  0.5074408
#> 8  1230    616    614  0.5008130  0.4991870  0.4491759  0.5508241
#> 9  1207    553    654  0.4581607  0.5418393  0.4027790  0.5972210
#> 10 1233    494    739  0.4006488  0.5993512  0.3509261  0.6490739
#> 11 1234    465    769  0.3768233  0.6231767  0.2630181  0.7369819
#>     raw_resid.0  raw_resid.1
#> 1  -0.024640641  0.024640641
#> 2  -0.009019180  0.009019180
#> 3  -0.026852795  0.026852795
#> 4   0.007858099 -0.007858099
#> 5   0.009042942 -0.009042942
#> 6   0.016694048 -0.016694048
#> 7   0.028700633 -0.028700633
#> 8   0.051637085 -0.051637085
#> 9   0.055381721 -0.055381721
#> 10  0.049722759 -0.049722759
#> 11  0.113805214 -0.113805214


##----------------------------------------------------------------------------
## Step 3: Draw the IRT residual plots 
# 1. the dichotomous item
# (1) both raw and standardized residual plots using the object "fit1"  
plot(x=fit1, item.loc=1, type = "both", ci.method = "wald",  ylim.sr.adjust=TRUE)

#>                               theta   N freq.0 freq.1 obs.prop.0
#> [-0.1218815,0.08512996] -0.02529272   3      3      0  1.0000000
#> (0.08512996,0.2921415]   0.18431014   5      2      3  0.4000000
#> (0.2921415,0.499153]     0.39488272  14      8      6  0.5714286
#> (0.499153,0.7061645]     0.60618911  60     34     26  0.5666667
#> (0.7061645,0.913176]     0.83531169 185     99     86  0.5351351
#> (0.913176,1.120187]      1.04723712 240    115    125  0.4791667
#> (1.120187,1.327199]      1.25232143 349    145    204  0.4154728
#> (1.327199,1.53421]       1.47877397 325    114    211  0.3507692
#> (1.53421,1.741222]       1.63898436 246     82    164  0.3333333
#> (1.741222,1.948233]      1.78810197 377    139    238  0.3687003
#> (1.948233,2.155245]      2.11166019 214     78    136  0.3644860
#>                         obs.prop.1 exp.prob.0 exp.prob.1 raw_resid.0
#> [-0.1218815,0.08512996]  0.0000000  0.7841844  0.2158156  0.21581559
#> (0.08512996,0.2921415]   0.6000000  0.7499556  0.2500444 -0.34995561
#> (0.2921415,0.499153]     0.4285714  0.7121079  0.2878921 -0.14067932
#> (0.499153,0.7061645]     0.4333333  0.6708959  0.3291041 -0.10422928
#> (0.7061645,0.913176]     0.4648649  0.6230537  0.3769463 -0.08791853
#> (0.913176,1.120187]      0.5208333  0.5765337  0.4234663 -0.09736699
#> (1.120187,1.327199]      0.5845272  0.5301760  0.4698240 -0.11470327
#> (1.327199,1.53421]       0.6492308  0.4784096  0.5215904 -0.12764036
#> (1.53421,1.741222]       0.6666667  0.4419993  0.5580007 -0.10866594
#> (1.741222,1.948233]      0.6312997  0.4086532  0.5913468 -0.03995295
#> (1.948233,2.155245]      0.6355140  0.3394647  0.6605353  0.02502128
#>                         raw_resid.1       se.0       se.1 std_resid.0
#> [-0.1218815,0.08512996] -0.21581559 0.23751437 0.23751437   0.9086423
#> (0.08512996,0.2921415]   0.34995561 0.19366063 0.19366063  -1.8070560
#> (0.2921415,0.499153]     0.14067932 0.12101070 0.12101070  -1.1625362
#> (0.499153,0.7061645]     0.10422928 0.06066226 0.06066226  -1.7181899
#> (0.7061645,0.913176]     0.08791853 0.03563007 0.03563007  -2.4675377
#> (0.913176,1.120187]      0.09736699 0.03189453 0.03189453  -3.0527806
#> (1.120187,1.327199]      0.11470327 0.02671560 0.02671560  -4.2934941
#> (1.327199,1.53421]       0.12764036 0.02770914 0.02770914  -4.6064351
#> (1.53421,1.741222]       0.10866594 0.03166362 0.03166362  -3.4318859
#> (1.741222,1.948233]      0.03995295 0.02531791 0.02531791  -1.5780508
#> (1.948233,2.155245]     -0.02502128 0.03236968 0.03236968   0.7729850
#>                         std_resid.1 raw.resid.0 raw.resid.1     se.0.1
#> [-0.1218815,0.08512996]  -0.9086423  0.21581559 -0.21581559 0.23751437
#> (0.08512996,0.2921415]    1.8070560 -0.34995561  0.34995561 0.19366063
#> (0.2921415,0.499153]      1.1625362 -0.14067932  0.14067932 0.12101070
#> (0.499153,0.7061645]      1.7181899 -0.10422928  0.10422928 0.06066226
#> (0.7061645,0.913176]      2.4675377 -0.08791853  0.08791853 0.03563007
#> (0.913176,1.120187]       3.0527806 -0.09736699  0.09736699 0.03189453
#> (1.120187,1.327199]       4.2934941 -0.11470327  0.11470327 0.02671560
#> (1.327199,1.53421]        4.6064351 -0.12764036  0.12764036 0.02770914
#> (1.53421,1.741222]        3.4318859 -0.10866594  0.10866594 0.03166362
#> (1.741222,1.948233]       1.5780508 -0.03995295  0.03995295 0.02531791
#> (1.948233,2.155245]      -0.7729850  0.02502128 -0.02502128 0.03236968
#>                             se.1.1 std.resid.0 std.resid.1
#> [-0.1218815,0.08512996] 0.23751437   0.9086423  -0.9086423
#> (0.08512996,0.2921415]  0.19366063  -1.8070560   1.8070560
#> (0.2921415,0.499153]    0.12101070  -1.1625362   1.1625362
#> (0.499153,0.7061645]    0.06066226  -1.7181899   1.7181899
#> (0.7061645,0.913176]    0.03563007  -2.4675377   2.4675377
#> (0.913176,1.120187]     0.03189453  -3.0527806   3.0527806
#> (1.120187,1.327199]     0.02671560  -4.2934941   4.2934941
#> (1.327199,1.53421]      0.02770914  -4.6064351   4.6064351
#> (1.53421,1.741222]      0.03166362  -3.4318859   3.4318859
#> (1.741222,1.948233]     0.02531791  -1.5780508   1.5780508
#> (1.948233,2.155245]     0.03236968   0.7729850  -0.7729850

# (2) the raw residual plots using the object "fit1"  
plot(x=fit1, item.loc=1, type = "icc", ci.method = "wald",  ylim.sr.adjust=TRUE)

#>                               theta   N freq.0 freq.1 obs.prop.0
#> [-0.1218815,0.08512996] -0.02529272   3      3      0  1.0000000
#> (0.08512996,0.2921415]   0.18431014   5      2      3  0.4000000
#> (0.2921415,0.499153]     0.39488272  14      8      6  0.5714286
#> (0.499153,0.7061645]     0.60618911  60     34     26  0.5666667
#> (0.7061645,0.913176]     0.83531169 185     99     86  0.5351351
#> (0.913176,1.120187]      1.04723712 240    115    125  0.4791667
#> (1.120187,1.327199]      1.25232143 349    145    204  0.4154728
#> (1.327199,1.53421]       1.47877397 325    114    211  0.3507692
#> (1.53421,1.741222]       1.63898436 246     82    164  0.3333333
#> (1.741222,1.948233]      1.78810197 377    139    238  0.3687003
#> (1.948233,2.155245]      2.11166019 214     78    136  0.3644860
#>                         obs.prop.1 exp.prob.0 exp.prob.1 raw_resid.0
#> [-0.1218815,0.08512996]  0.0000000  0.7841844  0.2158156  0.21581559
#> (0.08512996,0.2921415]   0.6000000  0.7499556  0.2500444 -0.34995561
#> (0.2921415,0.499153]     0.4285714  0.7121079  0.2878921 -0.14067932
#> (0.499153,0.7061645]     0.4333333  0.6708959  0.3291041 -0.10422928
#> (0.7061645,0.913176]     0.4648649  0.6230537  0.3769463 -0.08791853
#> (0.913176,1.120187]      0.5208333  0.5765337  0.4234663 -0.09736699
#> (1.120187,1.327199]      0.5845272  0.5301760  0.4698240 -0.11470327
#> (1.327199,1.53421]       0.6492308  0.4784096  0.5215904 -0.12764036
#> (1.53421,1.741222]       0.6666667  0.4419993  0.5580007 -0.10866594
#> (1.741222,1.948233]      0.6312997  0.4086532  0.5913468 -0.03995295
#> (1.948233,2.155245]      0.6355140  0.3394647  0.6605353  0.02502128
#>                         raw_resid.1       se.0       se.1 std_resid.0
#> [-0.1218815,0.08512996] -0.21581559 0.23751437 0.23751437   0.9086423
#> (0.08512996,0.2921415]   0.34995561 0.19366063 0.19366063  -1.8070560
#> (0.2921415,0.499153]     0.14067932 0.12101070 0.12101070  -1.1625362
#> (0.499153,0.7061645]     0.10422928 0.06066226 0.06066226  -1.7181899
#> (0.7061645,0.913176]     0.08791853 0.03563007 0.03563007  -2.4675377
#> (0.913176,1.120187]      0.09736699 0.03189453 0.03189453  -3.0527806
#> (1.120187,1.327199]      0.11470327 0.02671560 0.02671560  -4.2934941
#> (1.327199,1.53421]       0.12764036 0.02770914 0.02770914  -4.6064351
#> (1.53421,1.741222]       0.10866594 0.03166362 0.03166362  -3.4318859
#> (1.741222,1.948233]      0.03995295 0.02531791 0.02531791  -1.5780508
#> (1.948233,2.155245]     -0.02502128 0.03236968 0.03236968   0.7729850
#>                         std_resid.1 raw.resid.0 raw.resid.1     se.0.1
#> [-0.1218815,0.08512996]  -0.9086423  0.21581559 -0.21581559 0.23751437
#> (0.08512996,0.2921415]    1.8070560 -0.34995561  0.34995561 0.19366063
#> (0.2921415,0.499153]      1.1625362 -0.14067932  0.14067932 0.12101070
#> (0.499153,0.7061645]      1.7181899 -0.10422928  0.10422928 0.06066226
#> (0.7061645,0.913176]      2.4675377 -0.08791853  0.08791853 0.03563007
#> (0.913176,1.120187]       3.0527806 -0.09736699  0.09736699 0.03189453
#> (1.120187,1.327199]       4.2934941 -0.11470327  0.11470327 0.02671560
#> (1.327199,1.53421]        4.6064351 -0.12764036  0.12764036 0.02770914
#> (1.53421,1.741222]        3.4318859 -0.10866594  0.10866594 0.03166362
#> (1.741222,1.948233]       1.5780508 -0.03995295  0.03995295 0.02531791
#> (1.948233,2.155245]      -0.7729850  0.02502128 -0.02502128 0.03236968
#>                             se.1.1 std.resid.0 std.resid.1
#> [-0.1218815,0.08512996] 0.23751437   0.9086423  -0.9086423
#> (0.08512996,0.2921415]  0.19366063  -1.8070560   1.8070560
#> (0.2921415,0.499153]    0.12101070  -1.1625362   1.1625362
#> (0.499153,0.7061645]    0.06066226  -1.7181899   1.7181899
#> (0.7061645,0.913176]    0.03563007  -2.4675377   2.4675377
#> (0.913176,1.120187]     0.03189453  -3.0527806   3.0527806
#> (1.120187,1.327199]     0.02671560  -4.2934941   4.2934941
#> (1.327199,1.53421]      0.02770914  -4.6064351   4.6064351
#> (1.53421,1.741222]      0.03166362  -3.4318859   3.4318859
#> (1.741222,1.948233]     0.02531791  -1.5780508   1.5780508
#> (1.948233,2.155245]     0.03236968   0.7729850  -0.7729850

# (3) the standardized residual plots using the object "fit1"  
plot(x=fit1, item.loc=113, type = "sr", ci.method = "wald",  ylim.sr.adjust=TRUE)

#>                           theta   N freq.0 freq.1 freq.2 freq.3 obs.prop.0
#> [0.3564295,0.5199582] 0.3564295   1      1      0      0      0 1.00000000
#> (0.5199582,0.6834869] 0.6081321   5      3      2      0      0 0.60000000
#> (0.6834869,0.8470155] 0.7400138  15      5     10      0      0 0.33333333
#> (0.8470155,1.010544]  0.8866202  55      5     15     34      1 0.09090909
#> (1.010544,1.174073]   1.0821064 133      6     40     53     34 0.04511278
#> (1.174073,1.337602]   1.2832293 260      8     37    153     62 0.03076923
#> (1.337602,1.50113]    1.4747336  98      0     23     57     18 0.00000000
#> (1.50113,1.664659]    1.5311735 306      0      7     85    214 0.00000000
#> (1.664659,1.828188]   1.7632607 418      0      0    145    273 0.00000000
#> (1.828188,1.991716]   1.8577191  69      0      0      0     69 0.00000000
#> (1.991716,2.155245]   2.1021956 263      0      0      0    263 0.00000000
#>                       obs.prop.1 obs.prop.2 obs.prop.3  exp.prob.0
#> [0.3564295,0.5199582] 0.00000000  0.0000000 0.00000000 0.196511833
#> (0.5199582,0.6834869] 0.40000000  0.0000000 0.00000000 0.130431315
#> (0.6834869,0.8470155] 0.66666667  0.0000000 0.00000000 0.102631449
#> (0.8470155,1.010544]  0.27272727  0.6181818 0.01818182 0.077129446
#> (1.010544,1.174073]   0.30075188  0.3984962 0.25563910 0.051169395
#> (1.174073,1.337602]   0.14230769  0.5884615 0.23846154 0.032494074
#> (1.337602,1.50113]    0.23469388  0.5816327 0.18367347 0.020534959
#> (1.50113,1.664659]    0.02287582  0.2777778 0.69934641 0.017857642
#> (1.664659,1.828188]   0.00000000  0.3468900 0.65311005 0.009866868
#> (1.828188,1.991716]   0.00000000  0.0000000 1.00000000 0.007690015
#> (1.991716,2.155245]   0.00000000  0.0000000 1.00000000 0.003962699
#>                       exp.prob.1 exp.prob.2 exp.prob.3  raw_resid.0
#> [0.3564295,0.5199582] 0.31299790  0.3472692  0.1432210  0.803488167
#> (0.5199582,0.6834869] 0.27025065  0.3900531  0.2092649  0.469568685
#> (0.6834869,0.8470155] 0.24407213  0.4043226  0.2489738  0.230701885
#> (0.8470155,1.010544]  0.21379299  0.4127992  0.2962784  0.013779645
#> (1.010544,1.174073]   0.17398130  0.4120662  0.3627831 -0.006056613
#> (1.174073,1.337602]   0.13632441  0.3983962  0.4327853 -0.001724843
#> (1.337602,1.50113]    0.10523862  0.3756891  0.4985373 -0.020534959
#> (1.50113,1.664659]    0.09707782  0.3676106  0.5174539 -0.017857642
#> (1.664659,1.828188]   0.06836048  0.3299158  0.5918569 -0.009866868
#> (1.828188,1.991716]   0.05880602  0.3132481  0.6202558 -0.007690015
#> (1.991716,2.155245]   0.03912356  0.2690653  0.6878484 -0.003962699
#>                        raw_resid.1 raw_resid.2 raw_resid.3        se.0
#> [0.3564295,0.5199582] -0.312997903 -0.34726922 -0.14322104 0.397359953
#> (0.5199582,0.6834869]  0.129749354 -0.39005312 -0.20926492 0.150611412
#> (0.6834869,0.8470155]  0.422594537 -0.40432265 -0.24897378 0.078357401
#> (0.8470155,1.010544]   0.058934282  0.20538261 -0.27809653 0.035974863
#> (1.010544,1.174073]    0.126770584 -0.01356995 -0.10714402 0.019106171
#> (1.174073,1.337602]    0.005983284  0.19006531 -0.19432375 0.010996190
#> (1.337602,1.50113]     0.129455259  0.20594357 -0.31486387 0.014326112
#> (1.50113,1.664659]    -0.074201998 -0.08983281  0.18189246 0.007570744
#> (1.664659,1.828188]   -0.068360484  0.01697418  0.06125317 0.004834464
#> (1.828188,1.991716]   -0.058806016 -0.31324812  0.37974416 0.010516294
#> (1.991716,2.155245]   -0.039123555 -0.26906531  0.31215156 0.003873963
#>                             se.1       se.2       se.3 std_resid.0
#> [0.3564295,0.5199582] 0.46371351 0.47610220 0.35029812   2.0220663
#> (0.5199582,0.6834869] 0.19860274 0.21813376 0.18191928   3.1177497
#> (0.6834869,0.8470155] 0.11090564 0.12671381 0.11165000   2.9442258
#> (0.8470155,1.010544]  0.05528201 0.06638675 0.06156999   0.3830354
#> (1.010544,1.174073]   0.03287157 0.04267975 0.04169091  -0.3169978
#> (1.174073,1.337602]   0.02128019 0.03036171 0.03072722  -0.1568583
#> (1.337602,1.50113]    0.03099761 0.04892172 0.05050741  -1.4333937
#> (1.50113,1.664659]    0.01692484 0.02756294 0.02856568  -2.3587698
#> (1.664659,1.828188]   0.01234350 0.02299737 0.02403956  -2.0409436
#> (1.828188,1.991716]   0.02832213 0.05583668 0.05842604  -0.7312476
#> (1.991716,2.155245]   0.01195570 0.02734578 0.02857270  -1.0229057
#>                       std_resid.1 std_resid.2 std_resid.3  raw.resid.0
#> [0.3564295,0.5199582]  -0.6749812  -0.7294006  -0.4088547  0.803488167
#> (0.5199582,0.6834869]   0.6533110  -1.7881373  -1.1503175  0.469568685
#> (0.6834869,0.8470155]   3.8103971  -3.1908333  -2.2299488  0.230701885
#> (0.8470155,1.010544]    1.0660662   3.0937290  -4.5167547  0.013779645
#> (1.010544,1.174073]     3.8565422  -0.3179482  -2.5699613 -0.006056613
#> (1.174073,1.337602]     0.2811669   6.2600333  -6.3241558 -0.001724843
#> (1.337602,1.50113]      4.1762987   4.2096551  -6.2340132 -0.020534959
#> (1.50113,1.664659]     -4.3842081  -3.2591881   6.3675177 -0.017857642
#> (1.664659,1.828188]    -5.5381760   0.7380923   2.5480159 -0.009866868
#> (1.828188,1.991716]    -2.0763275  -5.6100775   6.4995706 -0.007690015
#> (1.991716,2.155245]    -3.2723764  -9.8393733  10.9248190 -0.003962699
#>                        raw.resid.1 raw.resid.2 raw.resid.3      se.0.1
#> [0.3564295,0.5199582] -0.312997903 -0.34726922 -0.14322104 0.397359953
#> (0.5199582,0.6834869]  0.129749354 -0.39005312 -0.20926492 0.150611412
#> (0.6834869,0.8470155]  0.422594537 -0.40432265 -0.24897378 0.078357401
#> (0.8470155,1.010544]   0.058934282  0.20538261 -0.27809653 0.035974863
#> (1.010544,1.174073]    0.126770584 -0.01356995 -0.10714402 0.019106171
#> (1.174073,1.337602]    0.005983284  0.19006531 -0.19432375 0.010996190
#> (1.337602,1.50113]     0.129455259  0.20594357 -0.31486387 0.014326112
#> (1.50113,1.664659]    -0.074201998 -0.08983281  0.18189246 0.007570744
#> (1.664659,1.828188]   -0.068360484  0.01697418  0.06125317 0.004834464
#> (1.828188,1.991716]   -0.058806016 -0.31324812  0.37974416 0.010516294
#> (1.991716,2.155245]   -0.039123555 -0.26906531  0.31215156 0.003873963
#>                           se.1.1     se.2.1     se.3.1 std.resid.0
#> [0.3564295,0.5199582] 0.46371351 0.47610220 0.35029812   2.0220663
#> (0.5199582,0.6834869] 0.19860274 0.21813376 0.18191928   3.1177497
#> (0.6834869,0.8470155] 0.11090564 0.12671381 0.11165000   2.9442258
#> (0.8470155,1.010544]  0.05528201 0.06638675 0.06156999   0.3830354
#> (1.010544,1.174073]   0.03287157 0.04267975 0.04169091  -0.3169978
#> (1.174073,1.337602]   0.02128019 0.03036171 0.03072722  -0.1568583
#> (1.337602,1.50113]    0.03099761 0.04892172 0.05050741  -1.4333937
#> (1.50113,1.664659]    0.01692484 0.02756294 0.02856568  -2.3587698
#> (1.664659,1.828188]   0.01234350 0.02299737 0.02403956  -2.0409436
#> (1.828188,1.991716]   0.02832213 0.05583668 0.05842604  -0.7312476
#> (1.991716,2.155245]   0.01195570 0.02734578 0.02857270  -1.0229057
#>                       std.resid.1 std.resid.2 std.resid.3
#> [0.3564295,0.5199582]  -0.6749812  -0.7294006  -0.4088547
#> (0.5199582,0.6834869]   0.6533110  -1.7881373  -1.1503175
#> (0.6834869,0.8470155]   3.8103971  -3.1908333  -2.2299488
#> (0.8470155,1.010544]    1.0660662   3.0937290  -4.5167547
#> (1.010544,1.174073]     3.8565422  -0.3179482  -2.5699613
#> (1.174073,1.337602]     0.2811669   6.2600333  -6.3241558
#> (1.337602,1.50113]      4.1762987   4.2096551  -6.2340132
#> (1.50113,1.664659]     -4.3842081  -3.2591881   6.3675177
#> (1.664659,1.828188]    -5.5381760   0.7380923   2.5480159
#> (1.828188,1.991716]    -2.0763275  -5.6100775   6.4995706
#> (1.991716,2.155245]    -3.2723764  -9.8393733  10.9248190

# 2. the polytomous item
# (1) both raw and standardized residual plots using the object "fit1"  
plot(x=fit1, item.loc=113, type = "both", ci.method = "wald",  ylim.sr.adjust=TRUE)

#>                           theta   N freq.0 freq.1 freq.2 freq.3 obs.prop.0
#> [0.3564295,0.5199582] 0.3564295   1      1      0      0      0 1.00000000
#> (0.5199582,0.6834869] 0.6081321   5      3      2      0      0 0.60000000
#> (0.6834869,0.8470155] 0.7400138  15      5     10      0      0 0.33333333
#> (0.8470155,1.010544]  0.8866202  55      5     15     34      1 0.09090909
#> (1.010544,1.174073]   1.0821064 133      6     40     53     34 0.04511278
#> (1.174073,1.337602]   1.2832293 260      8     37    153     62 0.03076923
#> (1.337602,1.50113]    1.4747336  98      0     23     57     18 0.00000000
#> (1.50113,1.664659]    1.5311735 306      0      7     85    214 0.00000000
#> (1.664659,1.828188]   1.7632607 418      0      0    145    273 0.00000000
#> (1.828188,1.991716]   1.8577191  69      0      0      0     69 0.00000000
#> (1.991716,2.155245]   2.1021956 263      0      0      0    263 0.00000000
#>                       obs.prop.1 obs.prop.2 obs.prop.3  exp.prob.0
#> [0.3564295,0.5199582] 0.00000000  0.0000000 0.00000000 0.196511833
#> (0.5199582,0.6834869] 0.40000000  0.0000000 0.00000000 0.130431315
#> (0.6834869,0.8470155] 0.66666667  0.0000000 0.00000000 0.102631449
#> (0.8470155,1.010544]  0.27272727  0.6181818 0.01818182 0.077129446
#> (1.010544,1.174073]   0.30075188  0.3984962 0.25563910 0.051169395
#> (1.174073,1.337602]   0.14230769  0.5884615 0.23846154 0.032494074
#> (1.337602,1.50113]    0.23469388  0.5816327 0.18367347 0.020534959
#> (1.50113,1.664659]    0.02287582  0.2777778 0.69934641 0.017857642
#> (1.664659,1.828188]   0.00000000  0.3468900 0.65311005 0.009866868
#> (1.828188,1.991716]   0.00000000  0.0000000 1.00000000 0.007690015
#> (1.991716,2.155245]   0.00000000  0.0000000 1.00000000 0.003962699
#>                       exp.prob.1 exp.prob.2 exp.prob.3  raw_resid.0
#> [0.3564295,0.5199582] 0.31299790  0.3472692  0.1432210  0.803488167
#> (0.5199582,0.6834869] 0.27025065  0.3900531  0.2092649  0.469568685
#> (0.6834869,0.8470155] 0.24407213  0.4043226  0.2489738  0.230701885
#> (0.8470155,1.010544]  0.21379299  0.4127992  0.2962784  0.013779645
#> (1.010544,1.174073]   0.17398130  0.4120662  0.3627831 -0.006056613
#> (1.174073,1.337602]   0.13632441  0.3983962  0.4327853 -0.001724843
#> (1.337602,1.50113]    0.10523862  0.3756891  0.4985373 -0.020534959
#> (1.50113,1.664659]    0.09707782  0.3676106  0.5174539 -0.017857642
#> (1.664659,1.828188]   0.06836048  0.3299158  0.5918569 -0.009866868
#> (1.828188,1.991716]   0.05880602  0.3132481  0.6202558 -0.007690015
#> (1.991716,2.155245]   0.03912356  0.2690653  0.6878484 -0.003962699
#>                        raw_resid.1 raw_resid.2 raw_resid.3        se.0
#> [0.3564295,0.5199582] -0.312997903 -0.34726922 -0.14322104 0.397359953
#> (0.5199582,0.6834869]  0.129749354 -0.39005312 -0.20926492 0.150611412
#> (0.6834869,0.8470155]  0.422594537 -0.40432265 -0.24897378 0.078357401
#> (0.8470155,1.010544]   0.058934282  0.20538261 -0.27809653 0.035974863
#> (1.010544,1.174073]    0.126770584 -0.01356995 -0.10714402 0.019106171
#> (1.174073,1.337602]    0.005983284  0.19006531 -0.19432375 0.010996190
#> (1.337602,1.50113]     0.129455259  0.20594357 -0.31486387 0.014326112
#> (1.50113,1.664659]    -0.074201998 -0.08983281  0.18189246 0.007570744
#> (1.664659,1.828188]   -0.068360484  0.01697418  0.06125317 0.004834464
#> (1.828188,1.991716]   -0.058806016 -0.31324812  0.37974416 0.010516294
#> (1.991716,2.155245]   -0.039123555 -0.26906531  0.31215156 0.003873963
#>                             se.1       se.2       se.3 std_resid.0
#> [0.3564295,0.5199582] 0.46371351 0.47610220 0.35029812   2.0220663
#> (0.5199582,0.6834869] 0.19860274 0.21813376 0.18191928   3.1177497
#> (0.6834869,0.8470155] 0.11090564 0.12671381 0.11165000   2.9442258
#> (0.8470155,1.010544]  0.05528201 0.06638675 0.06156999   0.3830354
#> (1.010544,1.174073]   0.03287157 0.04267975 0.04169091  -0.3169978
#> (1.174073,1.337602]   0.02128019 0.03036171 0.03072722  -0.1568583
#> (1.337602,1.50113]    0.03099761 0.04892172 0.05050741  -1.4333937
#> (1.50113,1.664659]    0.01692484 0.02756294 0.02856568  -2.3587698
#> (1.664659,1.828188]   0.01234350 0.02299737 0.02403956  -2.0409436
#> (1.828188,1.991716]   0.02832213 0.05583668 0.05842604  -0.7312476
#> (1.991716,2.155245]   0.01195570 0.02734578 0.02857270  -1.0229057
#>                       std_resid.1 std_resid.2 std_resid.3  raw.resid.0
#> [0.3564295,0.5199582]  -0.6749812  -0.7294006  -0.4088547  0.803488167
#> (0.5199582,0.6834869]   0.6533110  -1.7881373  -1.1503175  0.469568685
#> (0.6834869,0.8470155]   3.8103971  -3.1908333  -2.2299488  0.230701885
#> (0.8470155,1.010544]    1.0660662   3.0937290  -4.5167547  0.013779645
#> (1.010544,1.174073]     3.8565422  -0.3179482  -2.5699613 -0.006056613
#> (1.174073,1.337602]     0.2811669   6.2600333  -6.3241558 -0.001724843
#> (1.337602,1.50113]      4.1762987   4.2096551  -6.2340132 -0.020534959
#> (1.50113,1.664659]     -4.3842081  -3.2591881   6.3675177 -0.017857642
#> (1.664659,1.828188]    -5.5381760   0.7380923   2.5480159 -0.009866868
#> (1.828188,1.991716]    -2.0763275  -5.6100775   6.4995706 -0.007690015
#> (1.991716,2.155245]    -3.2723764  -9.8393733  10.9248190 -0.003962699
#>                        raw.resid.1 raw.resid.2 raw.resid.3      se.0.1
#> [0.3564295,0.5199582] -0.312997903 -0.34726922 -0.14322104 0.397359953
#> (0.5199582,0.6834869]  0.129749354 -0.39005312 -0.20926492 0.150611412
#> (0.6834869,0.8470155]  0.422594537 -0.40432265 -0.24897378 0.078357401
#> (0.8470155,1.010544]   0.058934282  0.20538261 -0.27809653 0.035974863
#> (1.010544,1.174073]    0.126770584 -0.01356995 -0.10714402 0.019106171
#> (1.174073,1.337602]    0.005983284  0.19006531 -0.19432375 0.010996190
#> (1.337602,1.50113]     0.129455259  0.20594357 -0.31486387 0.014326112
#> (1.50113,1.664659]    -0.074201998 -0.08983281  0.18189246 0.007570744
#> (1.664659,1.828188]   -0.068360484  0.01697418  0.06125317 0.004834464
#> (1.828188,1.991716]   -0.058806016 -0.31324812  0.37974416 0.010516294
#> (1.991716,2.155245]   -0.039123555 -0.26906531  0.31215156 0.003873963
#>                           se.1.1     se.2.1     se.3.1 std.resid.0
#> [0.3564295,0.5199582] 0.46371351 0.47610220 0.35029812   2.0220663
#> (0.5199582,0.6834869] 0.19860274 0.21813376 0.18191928   3.1177497
#> (0.6834869,0.8470155] 0.11090564 0.12671381 0.11165000   2.9442258
#> (0.8470155,1.010544]  0.05528201 0.06638675 0.06156999   0.3830354
#> (1.010544,1.174073]   0.03287157 0.04267975 0.04169091  -0.3169978
#> (1.174073,1.337602]   0.02128019 0.03036171 0.03072722  -0.1568583
#> (1.337602,1.50113]    0.03099761 0.04892172 0.05050741  -1.4333937
#> (1.50113,1.664659]    0.01692484 0.02756294 0.02856568  -2.3587698
#> (1.664659,1.828188]   0.01234350 0.02299737 0.02403956  -2.0409436
#> (1.828188,1.991716]   0.02832213 0.05583668 0.05842604  -0.7312476
#> (1.991716,2.155245]   0.01195570 0.02734578 0.02857270  -1.0229057
#>                       std.resid.1 std.resid.2 std.resid.3
#> [0.3564295,0.5199582]  -0.6749812  -0.7294006  -0.4088547
#> (0.5199582,0.6834869]   0.6533110  -1.7881373  -1.1503175
#> (0.6834869,0.8470155]   3.8103971  -3.1908333  -2.2299488
#> (0.8470155,1.010544]    1.0660662   3.0937290  -4.5167547
#> (1.010544,1.174073]     3.8565422  -0.3179482  -2.5699613
#> (1.174073,1.337602]     0.2811669   6.2600333  -6.3241558
#> (1.337602,1.50113]      4.1762987   4.2096551  -6.2340132
#> (1.50113,1.664659]     -4.3842081  -3.2591881   6.3675177
#> (1.664659,1.828188]    -5.5381760   0.7380923   2.5480159
#> (1.828188,1.991716]    -2.0763275  -5.6100775   6.4995706
#> (1.991716,2.155245]    -3.2723764  -9.8393733  10.9248190

# (2) the raw residual plots using the object "fit1"  
plot(x=fit1, item.loc=113, type = "icc", ci.method = "wald", layout.col=2, ylim.sr.adjust=TRUE)

#>                           theta   N freq.0 freq.1 freq.2 freq.3 obs.prop.0
#> [0.3564295,0.5199582] 0.3564295   1      1      0      0      0 1.00000000
#> (0.5199582,0.6834869] 0.6081321   5      3      2      0      0 0.60000000
#> (0.6834869,0.8470155] 0.7400138  15      5     10      0      0 0.33333333
#> (0.8470155,1.010544]  0.8866202  55      5     15     34      1 0.09090909
#> (1.010544,1.174073]   1.0821064 133      6     40     53     34 0.04511278
#> (1.174073,1.337602]   1.2832293 260      8     37    153     62 0.03076923
#> (1.337602,1.50113]    1.4747336  98      0     23     57     18 0.00000000
#> (1.50113,1.664659]    1.5311735 306      0      7     85    214 0.00000000
#> (1.664659,1.828188]   1.7632607 418      0      0    145    273 0.00000000
#> (1.828188,1.991716]   1.8577191  69      0      0      0     69 0.00000000
#> (1.991716,2.155245]   2.1021956 263      0      0      0    263 0.00000000
#>                       obs.prop.1 obs.prop.2 obs.prop.3  exp.prob.0
#> [0.3564295,0.5199582] 0.00000000  0.0000000 0.00000000 0.196511833
#> (0.5199582,0.6834869] 0.40000000  0.0000000 0.00000000 0.130431315
#> (0.6834869,0.8470155] 0.66666667  0.0000000 0.00000000 0.102631449
#> (0.8470155,1.010544]  0.27272727  0.6181818 0.01818182 0.077129446
#> (1.010544,1.174073]   0.30075188  0.3984962 0.25563910 0.051169395
#> (1.174073,1.337602]   0.14230769  0.5884615 0.23846154 0.032494074
#> (1.337602,1.50113]    0.23469388  0.5816327 0.18367347 0.020534959
#> (1.50113,1.664659]    0.02287582  0.2777778 0.69934641 0.017857642
#> (1.664659,1.828188]   0.00000000  0.3468900 0.65311005 0.009866868
#> (1.828188,1.991716]   0.00000000  0.0000000 1.00000000 0.007690015
#> (1.991716,2.155245]   0.00000000  0.0000000 1.00000000 0.003962699
#>                       exp.prob.1 exp.prob.2 exp.prob.3  raw_resid.0
#> [0.3564295,0.5199582] 0.31299790  0.3472692  0.1432210  0.803488167
#> (0.5199582,0.6834869] 0.27025065  0.3900531  0.2092649  0.469568685
#> (0.6834869,0.8470155] 0.24407213  0.4043226  0.2489738  0.230701885
#> (0.8470155,1.010544]  0.21379299  0.4127992  0.2962784  0.013779645
#> (1.010544,1.174073]   0.17398130  0.4120662  0.3627831 -0.006056613
#> (1.174073,1.337602]   0.13632441  0.3983962  0.4327853 -0.001724843
#> (1.337602,1.50113]    0.10523862  0.3756891  0.4985373 -0.020534959
#> (1.50113,1.664659]    0.09707782  0.3676106  0.5174539 -0.017857642
#> (1.664659,1.828188]   0.06836048  0.3299158  0.5918569 -0.009866868
#> (1.828188,1.991716]   0.05880602  0.3132481  0.6202558 -0.007690015
#> (1.991716,2.155245]   0.03912356  0.2690653  0.6878484 -0.003962699
#>                        raw_resid.1 raw_resid.2 raw_resid.3        se.0
#> [0.3564295,0.5199582] -0.312997903 -0.34726922 -0.14322104 0.397359953
#> (0.5199582,0.6834869]  0.129749354 -0.39005312 -0.20926492 0.150611412
#> (0.6834869,0.8470155]  0.422594537 -0.40432265 -0.24897378 0.078357401
#> (0.8470155,1.010544]   0.058934282  0.20538261 -0.27809653 0.035974863
#> (1.010544,1.174073]    0.126770584 -0.01356995 -0.10714402 0.019106171
#> (1.174073,1.337602]    0.005983284  0.19006531 -0.19432375 0.010996190
#> (1.337602,1.50113]     0.129455259  0.20594357 -0.31486387 0.014326112
#> (1.50113,1.664659]    -0.074201998 -0.08983281  0.18189246 0.007570744
#> (1.664659,1.828188]   -0.068360484  0.01697418  0.06125317 0.004834464
#> (1.828188,1.991716]   -0.058806016 -0.31324812  0.37974416 0.010516294
#> (1.991716,2.155245]   -0.039123555 -0.26906531  0.31215156 0.003873963
#>                             se.1       se.2       se.3 std_resid.0
#> [0.3564295,0.5199582] 0.46371351 0.47610220 0.35029812   2.0220663
#> (0.5199582,0.6834869] 0.19860274 0.21813376 0.18191928   3.1177497
#> (0.6834869,0.8470155] 0.11090564 0.12671381 0.11165000   2.9442258
#> (0.8470155,1.010544]  0.05528201 0.06638675 0.06156999   0.3830354
#> (1.010544,1.174073]   0.03287157 0.04267975 0.04169091  -0.3169978
#> (1.174073,1.337602]   0.02128019 0.03036171 0.03072722  -0.1568583
#> (1.337602,1.50113]    0.03099761 0.04892172 0.05050741  -1.4333937
#> (1.50113,1.664659]    0.01692484 0.02756294 0.02856568  -2.3587698
#> (1.664659,1.828188]   0.01234350 0.02299737 0.02403956  -2.0409436
#> (1.828188,1.991716]   0.02832213 0.05583668 0.05842604  -0.7312476
#> (1.991716,2.155245]   0.01195570 0.02734578 0.02857270  -1.0229057
#>                       std_resid.1 std_resid.2 std_resid.3  raw.resid.0
#> [0.3564295,0.5199582]  -0.6749812  -0.7294006  -0.4088547  0.803488167
#> (0.5199582,0.6834869]   0.6533110  -1.7881373  -1.1503175  0.469568685
#> (0.6834869,0.8470155]   3.8103971  -3.1908333  -2.2299488  0.230701885
#> (0.8470155,1.010544]    1.0660662   3.0937290  -4.5167547  0.013779645
#> (1.010544,1.174073]     3.8565422  -0.3179482  -2.5699613 -0.006056613
#> (1.174073,1.337602]     0.2811669   6.2600333  -6.3241558 -0.001724843
#> (1.337602,1.50113]      4.1762987   4.2096551  -6.2340132 -0.020534959
#> (1.50113,1.664659]     -4.3842081  -3.2591881   6.3675177 -0.017857642
#> (1.664659,1.828188]    -5.5381760   0.7380923   2.5480159 -0.009866868
#> (1.828188,1.991716]    -2.0763275  -5.6100775   6.4995706 -0.007690015
#> (1.991716,2.155245]    -3.2723764  -9.8393733  10.9248190 -0.003962699
#>                        raw.resid.1 raw.resid.2 raw.resid.3      se.0.1
#> [0.3564295,0.5199582] -0.312997903 -0.34726922 -0.14322104 0.397359953
#> (0.5199582,0.6834869]  0.129749354 -0.39005312 -0.20926492 0.150611412
#> (0.6834869,0.8470155]  0.422594537 -0.40432265 -0.24897378 0.078357401
#> (0.8470155,1.010544]   0.058934282  0.20538261 -0.27809653 0.035974863
#> (1.010544,1.174073]    0.126770584 -0.01356995 -0.10714402 0.019106171
#> (1.174073,1.337602]    0.005983284  0.19006531 -0.19432375 0.010996190
#> (1.337602,1.50113]     0.129455259  0.20594357 -0.31486387 0.014326112
#> (1.50113,1.664659]    -0.074201998 -0.08983281  0.18189246 0.007570744
#> (1.664659,1.828188]   -0.068360484  0.01697418  0.06125317 0.004834464
#> (1.828188,1.991716]   -0.058806016 -0.31324812  0.37974416 0.010516294
#> (1.991716,2.155245]   -0.039123555 -0.26906531  0.31215156 0.003873963
#>                           se.1.1     se.2.1     se.3.1 std.resid.0
#> [0.3564295,0.5199582] 0.46371351 0.47610220 0.35029812   2.0220663
#> (0.5199582,0.6834869] 0.19860274 0.21813376 0.18191928   3.1177497
#> (0.6834869,0.8470155] 0.11090564 0.12671381 0.11165000   2.9442258
#> (0.8470155,1.010544]  0.05528201 0.06638675 0.06156999   0.3830354
#> (1.010544,1.174073]   0.03287157 0.04267975 0.04169091  -0.3169978
#> (1.174073,1.337602]   0.02128019 0.03036171 0.03072722  -0.1568583
#> (1.337602,1.50113]    0.03099761 0.04892172 0.05050741  -1.4333937
#> (1.50113,1.664659]    0.01692484 0.02756294 0.02856568  -2.3587698
#> (1.664659,1.828188]   0.01234350 0.02299737 0.02403956  -2.0409436
#> (1.828188,1.991716]   0.02832213 0.05583668 0.05842604  -0.7312476
#> (1.991716,2.155245]   0.01195570 0.02734578 0.02857270  -1.0229057
#>                       std.resid.1 std.resid.2 std.resid.3
#> [0.3564295,0.5199582]  -0.6749812  -0.7294006  -0.4088547
#> (0.5199582,0.6834869]   0.6533110  -1.7881373  -1.1503175
#> (0.6834869,0.8470155]   3.8103971  -3.1908333  -2.2299488
#> (0.8470155,1.010544]    1.0660662   3.0937290  -4.5167547
#> (1.010544,1.174073]     3.8565422  -0.3179482  -2.5699613
#> (1.174073,1.337602]     0.2811669   6.2600333  -6.3241558
#> (1.337602,1.50113]      4.1762987   4.2096551  -6.2340132
#> (1.50113,1.664659]     -4.3842081  -3.2591881   6.3675177
#> (1.664659,1.828188]    -5.5381760   0.7380923   2.5480159
#> (1.828188,1.991716]    -2.0763275  -5.6100775   6.4995706
#> (1.991716,2.155245]    -3.2723764  -9.8393733  10.9248190

# (3) the standardized residual plots using the object "fit1"  
plot(x=fit1, item.loc=113, type = "sr", ci.method = "wald", layout.col=4, ylim.sr.adjust=TRUE)

#>                           theta   N freq.0 freq.1 freq.2 freq.3 obs.prop.0
#> [0.3564295,0.5199582] 0.3564295   1      1      0      0      0 1.00000000
#> (0.5199582,0.6834869] 0.6081321   5      3      2      0      0 0.60000000
#> (0.6834869,0.8470155] 0.7400138  15      5     10      0      0 0.33333333
#> (0.8470155,1.010544]  0.8866202  55      5     15     34      1 0.09090909
#> (1.010544,1.174073]   1.0821064 133      6     40     53     34 0.04511278
#> (1.174073,1.337602]   1.2832293 260      8     37    153     62 0.03076923
#> (1.337602,1.50113]    1.4747336  98      0     23     57     18 0.00000000
#> (1.50113,1.664659]    1.5311735 306      0      7     85    214 0.00000000
#> (1.664659,1.828188]   1.7632607 418      0      0    145    273 0.00000000
#> (1.828188,1.991716]   1.8577191  69      0      0      0     69 0.00000000
#> (1.991716,2.155245]   2.1021956 263      0      0      0    263 0.00000000
#>                       obs.prop.1 obs.prop.2 obs.prop.3  exp.prob.0
#> [0.3564295,0.5199582] 0.00000000  0.0000000 0.00000000 0.196511833
#> (0.5199582,0.6834869] 0.40000000  0.0000000 0.00000000 0.130431315
#> (0.6834869,0.8470155] 0.66666667  0.0000000 0.00000000 0.102631449
#> (0.8470155,1.010544]  0.27272727  0.6181818 0.01818182 0.077129446
#> (1.010544,1.174073]   0.30075188  0.3984962 0.25563910 0.051169395
#> (1.174073,1.337602]   0.14230769  0.5884615 0.23846154 0.032494074
#> (1.337602,1.50113]    0.23469388  0.5816327 0.18367347 0.020534959
#> (1.50113,1.664659]    0.02287582  0.2777778 0.69934641 0.017857642
#> (1.664659,1.828188]   0.00000000  0.3468900 0.65311005 0.009866868
#> (1.828188,1.991716]   0.00000000  0.0000000 1.00000000 0.007690015
#> (1.991716,2.155245]   0.00000000  0.0000000 1.00000000 0.003962699
#>                       exp.prob.1 exp.prob.2 exp.prob.3  raw_resid.0
#> [0.3564295,0.5199582] 0.31299790  0.3472692  0.1432210  0.803488167
#> (0.5199582,0.6834869] 0.27025065  0.3900531  0.2092649  0.469568685
#> (0.6834869,0.8470155] 0.24407213  0.4043226  0.2489738  0.230701885
#> (0.8470155,1.010544]  0.21379299  0.4127992  0.2962784  0.013779645
#> (1.010544,1.174073]   0.17398130  0.4120662  0.3627831 -0.006056613
#> (1.174073,1.337602]   0.13632441  0.3983962  0.4327853 -0.001724843
#> (1.337602,1.50113]    0.10523862  0.3756891  0.4985373 -0.020534959
#> (1.50113,1.664659]    0.09707782  0.3676106  0.5174539 -0.017857642
#> (1.664659,1.828188]   0.06836048  0.3299158  0.5918569 -0.009866868
#> (1.828188,1.991716]   0.05880602  0.3132481  0.6202558 -0.007690015
#> (1.991716,2.155245]   0.03912356  0.2690653  0.6878484 -0.003962699
#>                        raw_resid.1 raw_resid.2 raw_resid.3        se.0
#> [0.3564295,0.5199582] -0.312997903 -0.34726922 -0.14322104 0.397359953
#> (0.5199582,0.6834869]  0.129749354 -0.39005312 -0.20926492 0.150611412
#> (0.6834869,0.8470155]  0.422594537 -0.40432265 -0.24897378 0.078357401
#> (0.8470155,1.010544]   0.058934282  0.20538261 -0.27809653 0.035974863
#> (1.010544,1.174073]    0.126770584 -0.01356995 -0.10714402 0.019106171
#> (1.174073,1.337602]    0.005983284  0.19006531 -0.19432375 0.010996190
#> (1.337602,1.50113]     0.129455259  0.20594357 -0.31486387 0.014326112
#> (1.50113,1.664659]    -0.074201998 -0.08983281  0.18189246 0.007570744
#> (1.664659,1.828188]   -0.068360484  0.01697418  0.06125317 0.004834464
#> (1.828188,1.991716]   -0.058806016 -0.31324812  0.37974416 0.010516294
#> (1.991716,2.155245]   -0.039123555 -0.26906531  0.31215156 0.003873963
#>                             se.1       se.2       se.3 std_resid.0
#> [0.3564295,0.5199582] 0.46371351 0.47610220 0.35029812   2.0220663
#> (0.5199582,0.6834869] 0.19860274 0.21813376 0.18191928   3.1177497
#> (0.6834869,0.8470155] 0.11090564 0.12671381 0.11165000   2.9442258
#> (0.8470155,1.010544]  0.05528201 0.06638675 0.06156999   0.3830354
#> (1.010544,1.174073]   0.03287157 0.04267975 0.04169091  -0.3169978
#> (1.174073,1.337602]   0.02128019 0.03036171 0.03072722  -0.1568583
#> (1.337602,1.50113]    0.03099761 0.04892172 0.05050741  -1.4333937
#> (1.50113,1.664659]    0.01692484 0.02756294 0.02856568  -2.3587698
#> (1.664659,1.828188]   0.01234350 0.02299737 0.02403956  -2.0409436
#> (1.828188,1.991716]   0.02832213 0.05583668 0.05842604  -0.7312476
#> (1.991716,2.155245]   0.01195570 0.02734578 0.02857270  -1.0229057
#>                       std_resid.1 std_resid.2 std_resid.3  raw.resid.0
#> [0.3564295,0.5199582]  -0.6749812  -0.7294006  -0.4088547  0.803488167
#> (0.5199582,0.6834869]   0.6533110  -1.7881373  -1.1503175  0.469568685
#> (0.6834869,0.8470155]   3.8103971  -3.1908333  -2.2299488  0.230701885
#> (0.8470155,1.010544]    1.0660662   3.0937290  -4.5167547  0.013779645
#> (1.010544,1.174073]     3.8565422  -0.3179482  -2.5699613 -0.006056613
#> (1.174073,1.337602]     0.2811669   6.2600333  -6.3241558 -0.001724843
#> (1.337602,1.50113]      4.1762987   4.2096551  -6.2340132 -0.020534959
#> (1.50113,1.664659]     -4.3842081  -3.2591881   6.3675177 -0.017857642
#> (1.664659,1.828188]    -5.5381760   0.7380923   2.5480159 -0.009866868
#> (1.828188,1.991716]    -2.0763275  -5.6100775   6.4995706 -0.007690015
#> (1.991716,2.155245]    -3.2723764  -9.8393733  10.9248190 -0.003962699
#>                        raw.resid.1 raw.resid.2 raw.resid.3      se.0.1
#> [0.3564295,0.5199582] -0.312997903 -0.34726922 -0.14322104 0.397359953
#> (0.5199582,0.6834869]  0.129749354 -0.39005312 -0.20926492 0.150611412
#> (0.6834869,0.8470155]  0.422594537 -0.40432265 -0.24897378 0.078357401
#> (0.8470155,1.010544]   0.058934282  0.20538261 -0.27809653 0.035974863
#> (1.010544,1.174073]    0.126770584 -0.01356995 -0.10714402 0.019106171
#> (1.174073,1.337602]    0.005983284  0.19006531 -0.19432375 0.010996190
#> (1.337602,1.50113]     0.129455259  0.20594357 -0.31486387 0.014326112
#> (1.50113,1.664659]    -0.074201998 -0.08983281  0.18189246 0.007570744
#> (1.664659,1.828188]   -0.068360484  0.01697418  0.06125317 0.004834464
#> (1.828188,1.991716]   -0.058806016 -0.31324812  0.37974416 0.010516294
#> (1.991716,2.155245]   -0.039123555 -0.26906531  0.31215156 0.003873963
#>                           se.1.1     se.2.1     se.3.1 std.resid.0
#> [0.3564295,0.5199582] 0.46371351 0.47610220 0.35029812   2.0220663
#> (0.5199582,0.6834869] 0.19860274 0.21813376 0.18191928   3.1177497
#> (0.6834869,0.8470155] 0.11090564 0.12671381 0.11165000   2.9442258
#> (0.8470155,1.010544]  0.05528201 0.06638675 0.06156999   0.3830354
#> (1.010544,1.174073]   0.03287157 0.04267975 0.04169091  -0.3169978
#> (1.174073,1.337602]   0.02128019 0.03036171 0.03072722  -0.1568583
#> (1.337602,1.50113]    0.03099761 0.04892172 0.05050741  -1.4333937
#> (1.50113,1.664659]    0.01692484 0.02756294 0.02856568  -2.3587698
#> (1.664659,1.828188]   0.01234350 0.02299737 0.02403956  -2.0409436
#> (1.828188,1.991716]   0.02832213 0.05583668 0.05842604  -0.7312476
#> (1.991716,2.155245]   0.01195570 0.02734578 0.02857270  -1.0229057
#>                       std.resid.1 std.resid.2 std.resid.3
#> [0.3564295,0.5199582]  -0.6749812  -0.7294006  -0.4088547
#> (0.5199582,0.6834869]   0.6533110  -1.7881373  -1.1503175
#> (0.6834869,0.8470155]   3.8103971  -3.1908333  -2.2299488
#> (0.8470155,1.010544]    1.0660662   3.0937290  -4.5167547
#> (1.010544,1.174073]     3.8565422  -0.3179482  -2.5699613
#> (1.174073,1.337602]     0.2811669   6.2600333  -6.3241558
#> (1.337602,1.50113]      4.1762987   4.2096551  -6.2340132
#> (1.50113,1.664659]     -4.3842081  -3.2591881   6.3675177
#> (1.664659,1.828188]    -5.5381760   0.7380923   2.5480159
#> (1.828188,1.991716]    -2.0763275  -5.6100775   6.4995706
#> (1.991716,2.155245]    -3.2723764  -9.8393733  10.9248190