dgo: Dynamic Estimation of Group-Level Opinion

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dgo is an R package for the dynamic estimation of group-level public opinion. You can use the package to estimate latent trait means in subpopulations from survey data. For example, dgo can estimate the average policy liberalism in each American state over time among Democrats, Independents, and Republicans, given their answers to survey questions about policy proposals.

dgo accomplishes this using a Bayesian group-level IRT approach developed by Caughey and Warshaw 2015. It models latent traits at the level of demographic and geographic groups rather than individuals. It uses a hierarchical model to borrow strength cross-sectionally and dynamic linear models to do so across time.

The package can also be used to estimate smoothed estimates of subpopulations’ average responses to single survey items, using a dynamic multi-level regression and poststratification (MRP) model (Park, Gelman, and Bafumi 2004). For instance, you can use dgo to estimate public opinion in each state on same-sex marriage or the Affordable Care Act.

This model opens up new areas of research on historical public opinion in the United States at the subnational level. It also allows scholars of comparative politics to estimate dynamic cross-national models of public opinion.


dgo can be installed from CRAN:


Or get the latest version from GitHub using devtools:

if (!require(devtools, quietly = TRUE)) install.packages("devtools")

dgo requires a working installation of RStan. If you don’t have already have RStan, follow its “Getting Started” guide.


Load the package and set RStan’s recommended options for a local, multicore machine with excess RAM:

rstan_options(auto_write = TRUE)
options(mc.cores = parallel::detectCores())

The minimal workflow from raw data to estimation is:

  1. shape input data using the shape() function; and
  2. pass the result to the dgirt() function to estimate a latent trait (e.g., conservatism) or dgmrp() function to estimate opinion on a single survey question.


Please report issues that you encounter.

Contributing and citing

dgo is under development and we welcome suggestions.

The package citation is:

Dunham, James, Devin Caughey, and Christopher Warshaw. 2017. dgo: Dynamic Estimation of Group-level Opinion. R package. https://jdunham.io/dgo/.