cspp: Correlates of State Policy Project Package

#' Welfare policy data from IPPSR Correlates of State Policy Project v2.2
#'
#' The Correlates of State Policy Project includes more than 2000 variables,
#'  with observations across the 50 U.S. states and across time (1900-2016, approximately).
#'  These variables represent policy outputs or political, social, or economic factors
#'  that may influence policy differences. The codebook includes the variable name,
#'  a short description of the variable, the variable time frame,
#'  a longer description of the variable, and the variable source(s) and notes.
#'
#' This aggregated dataset is only possible because many scholars and students have spent
#'  countless hours creating, collecting, cleaning, and making data publicly available.
#'  Thus, if you use the dataset, please cite the original data sources.
#'
#'  @docType data
#'
#'  @usage data(welfare)
#'
#'  @format A data frame of 6120 rows and 30 variables. Each observation is year-state.
#'
#'  @keywords datasets
#'
#'  @references
#'  Jordan, Marty P. and Matt Grossmann. 2020. The Correlates of State Policy Project v.2.2.
#'   East Lansing, MI: Institute for Public Policy and Social Research (IPPSR).
#'
#'  @source \href{http://ippsr.msu.edu/public-policy/correlates-state-policy}
"welfare"