dgirt: Fit a dynamic group IRT or single-issue MRP model
In jamesdunham/dgirt: Dynamic Estimation of Group-Level Opinion

Description Usage Arguments Details Value

dgirt and dgmrp make calls to stan with the Stan code and data for their respective models.

dgirt(shaped_data, ..., separate_t = FALSE, delta_tbar_prior_mean = 0.65,
  delta_tbar_prior_sd = 0.25, innov_sd_delta_scale = 2.5,
  innov_sd_theta_scale = 2.5, version = "2017_01_04",
  hierarchical_model = TRUE, model = NULL)

dgmrp(shaped_data, ..., separate_t = FALSE, delta_tbar_prior_mean = 0.65,
  delta_tbar_prior_sd = 0.25, innov_sd_delta_scale = 2.5,
  innov_sd_theta_scale = 2.5, version = "2017_01_04_singleissue",
  model = NULL)

`shaped_data`	Output from `shape`.
`...`	Further arguments, passed to `stan`.
`separate_t`	Whether smoothing of estimates over time should be disabled. Default `FALSE`.
`delta_tbar_prior_mean`	Prior mean for `delta_tbar`, the normal weight on `theta_bar` in the previous period. Default `0.65`.
`delta_tbar_prior_sd`	Prior standard deviation for `delta_bar`. Default `0.25`.
`innov_sd_delta_scale`	Prior scale for `sd_innov_delta`, the Cauchy innovation standard deviation of `nu_geo` and `delta_gamma`. Default `2.5`.
`innov_sd_theta_scale`	Prior scale for `sd_innov_theta`, the Cauchy innovation standard deviation of `gamma`, `xi`, and if `constant_item` is `FALSE` the item difficulty `diff`. Default `2.5`.
`version`	The name of the dgo model to estimate, or the path to a `.stan` file. Valid names for dgo models are "2017_01_04", "2017_01_04_singleissue". Ignored if argument `model` is used.
`hierarchical_model`	Whether a hierarchical model should be used to smooth the group IRT estimates. If set to FALSE, the model will return raw group-IRT model estimates for each group. Default `TRUE`.
`model`	A Stan model object of class `stanmodel` to be used in estimation. Specifying this argument avoids repeated model compilation. Note that the Stan model object for a model fitted with `dgirt()` or `dgmrp()` can be found in the the `stanmodel` slot of the resulting `dgirt_fit` or `dgmrp_fit` object.

The user will typically pass further arguments to stan via the ... argument, at a minimum iter and cores.

By default dgirt and dgmrp override the stan default for its pars argument to specify typical parameters of interest. They also set iter_r to 1L.

Important: the dgirt model assumes consistent coding of the polarity of item responses for identification.

A dgo_fit-class object that extends stanfit-class.

jamesdunham/dgirt documentation built on May 18, 2019, 11:19 a.m.