o Included the function ‘llike_score’ to compute the loglikelihood function of ability for an examinee.

o Updated the function ‘est_item’ to find better starting values for item parameter calibration.

o Updated the function ‘est_item’ to exclude items that contains no item response data during the item parameter estimation.

o Updated the function ‘est_item’ to count the number of item responses for each item used to estimate the item parameters.

o Updated the function ‘est_score’ to find better starting values when MLE is used.

o Updated the function ‘est_score’ to address NaNs of gradient values and NaNs of hessian values when MLE, MLEF, or MAP is used.

o Fixed a problem of the function ‘est_score’, which returned an error message when a vector of an examinee’s response data was used in the argument of ‘x’.

o Fixed a problem of the function ‘est_score’, which returned an error message when only one dichotomous item or one polytomous item was included in the item meta data set.

o Fixed a problem of the function ‘est_item’, which returned an error message when the inverse of hessian matrix is not obtainable.

o Included the ‘maximum likelihood estimation with fences’ scoring method (Han, 2016) in the function ‘est_score’.

o Included the ‘inverse test characteristic curve (TCC)’ scoring method (e.g., Stocking, 1996) in the function ‘est_score’.

o Included the function ‘llike_item’ to compute the loglikelihood values of items.

o For the function ‘est_item’, default parameters of a-parameter prior distribution were revised

o Updated the function ‘est_item’ to find better starting values for item parameter calibration.

o Updated the function ‘est_score’ to estimate an ability in a brute force way when MLE or MAP fails to find the solution.

o Updated the function ‘irtfit’ to compute the likelihood ratio chi-square fit statistic (G2; Mckinley & Mills, 1985).

o initial release on CRAN