R/format_dgirt.R

In fsolt/DCPOtools: Tools for Dynamic Comparative Public Opinion

#' Format DCPO Data for Estimation Using DGIRT Stan Files
#'
#'  \code{format_dgirt} formats DCPO data output by \code{dcpo_setup} for use with the \code{dgo}
#'  package's \code{dgirt} Stan files.
#'
#' @param dcpo_data a data frame of survey responses generated by \code{dcpo_setup}
#'
#' @return a list of Stan data
#'
#' @importFrom reshape2 acast
#' @importFrom dplyr n_distinct mutate_all select
#' @importFrom tibble rownames_to_column
#'
#' @export

format_dgirt <- function(dcpo_data) {

    n_tkqr <- reshape2::acast(dcpo_data,
                              year ~ country ~ item ~ r,
                              fun.aggregate = sum,
                              value.var = "n",
                              drop = FALSE)

    unused_cp <- as.data.frame(apply(n_tkqr, c(3, 4), sum)) %>%
        tibble::rownames_to_column() %>%
        dplyr::mutate_all(~if_else(. > 0, 0, 1)) %>%
        dplyr::select(-`1`, -rowname) %>%
        as.matrix()

    dgirt_stan <- new('modgirt_in',
                      items = attr(n_tkqr, "dimnames")[[3]],
                      time = "year",
                      geo = "country",
                      demo = "country",
                      stan_data = list( G          = dplyr::n_distinct(dcpo_data$country),
                                        T          = max(dcpo_data$year) - min(dcpo_data$year) + 1,
                                        Q          = dplyr::n_distinct(dcpo_data$item),
                                        K          = max(dcpo_data$r),
                                        D          = 1,
                                        SSSS       = n_tkqr,
                                        beta_sign  = matrix(1, dplyr::n_distinct(dcpo_data$item), 1),
                                        unused_cut = unused_cp,
                                        N_nonzero  = sum(n_tkqr != 0),
                                        data       = dcpo_data)
    )

    return(dgirt_stan)
}

#' @export
modgirt_in <- setClass("modgirt_in",
                       slots = list(
                           items = "character",
                           time = "character",
                           geo = "character",
                           demo = "character",
                           stan_data = "list")
)