The Standardized World Income Inequality Database*

TLDR

Since 2008, the Standardized World Income Inequality Database (SWIID) has supplied income‑inequality data designed to maximize comparability while covering the widest range of countries and years. This article describes the current construction of SWIID, highlights differences from its original version, and reevaluates its utility for cross‑national income‑inequality research amid newer alternatives. The authors assess coverage across country‑years and evaluate comparability by predicting the gold‑standard Luxembourg Income Study before its data are released. SWIID provides twice the coverage of the next largest dataset and achieves three to eight times better comparability, making it the preferred source for cross‑national income‑inequality research.

Abstract

Objective Since 2008, the Standardized World Income Inequality Database (SWIID) has provided income inequality data that seek to maximize comparability while providing the broadest possible coverage of countries and years. This article describes the current SWIID's construction, highlighting differences from its original version, and reevaluates the SWIID's utility to cross‐national income inequality research in light of recently available alternatives. Methods Coverage of inequality data sets is assessed across country‐years; comparability is evaluated in terms of success in predicting the Luxembourg Income Study (LIS), recognized in the field as the gold standard in comparability, before those data are released. Results The SWIID offers coverage double that of the next largest income inequality data set, and its record of comparability is three to eight times better than those of alternate data sets. Conclusions As its coverage and comparability far exceed those of the alternatives, the SWIID remains better suited for broadly cross‐national research on income inequality than other available sources.