#' Reference list of countries and territories with small-island classifications
#'
#' A curated dataset of 251 countries and territories, including
#' sub-sovereign island jurisdictions (Aruba, Curacao, Bonaire,
#' Sint Maarten, the French overseas collectivities, Aaland Islands,
#' and others) that are typically collapsed or omitted by ISO 3166-1
#' country-code lists.
#'
#' @format A data frame with 251 rows and 13 columns:
#' \describe{
#'   \item{name}{Short common name (e.g. "Aruba", "Curacao", "Bonaire").}
#'   \item{label}{Display label, used by the upstream XLSForm survey.}
#'   \item{iso_code}{ISO 3166-1 alpha-2 code, with hyphenated extensions
#'     for the three BES islands (\code{BQ-BO} Bonaire, \code{BQ-SE}
#'     Sint Eustatius, \code{BQ-SA} Saba) so they can be distinguished
#'     within the shared \code{BQ} prefix.}
#'   \item{wb_region}{World Bank region.}
#'   \item{wb_income_group}{World Bank income group.}
#'   \item{political_association}{Sovereign power for non-independent
#'     territories; \code{"Independent"} otherwise.}
#'   \item{is_sids}{1 if a UN-DESA recognised Small Island Developing
#'     State (member or associate); 0 otherwise.}
#'   \item{sids_tier}{\code{"Sovereign member"}, \code{"Associate member"},
#'     or \code{NA} where not applicable.}
#'   \item{is_snij}{1 if a sub-national island jurisdiction; 0 otherwise.}
#'   \item{criterion_small}{1 if meets the small-population/small-area
#'     criterion; 0 otherwise.}
#'   \item{criterion_island}{1 if an island or archipelago; 0 otherwise.}
#'   \item{criterion_developing}{1 if classified as developing; 0 otherwise.}
#'   \item{criterion_sovereign}{1 if a sovereign state; 0 otherwise.}
#' }
#'
#' @source University of Aruba, Digital Competence Dutch Caribbean (DCDC)
#'   Network. \emph{island-research-reference-data}, CC BY 4.0.
#'   \url{https://github.com/University-of-Aruba/island-research-reference-data}
#'
#' @examples
#' head(islands)
#'
#' # SIDS by World Bank region
#' table(islands$wb_region[islands$is_sids == 1])
#'
#' # Dutch Kingdom territories (an example of the SNIJ axis)
#' islands[islands$political_association == "Dutch Kingdom",
#'         c("name", "iso_code", "is_sids", "is_snij")]
"islands"
