Shining a Light on Purchasing Power Parities
利用卫星记录的夜间灯光数据作为经济活动的独立基准，评估购买力平价调整后的GDP估计，发现其对贫穷国家的描述优于市场汇率法，且估计质量随时间改善，建议仅使用最新价格数据并持续修订。
We use satellite-recorded nighttime lights as an independent benchmark of economic activity in order to generate three findings in the study of PPP-adjusted estimates of GDP. First, PPP-adjusted estimates better describe poor economies than do market exchange rate-based estimates today, although this was not the case in the late 1990s. Second, estimates of PPPs have been steadily improving from one price survey round to the next. Third, it has tended to be optimal to only use the latest price data and to revise existing PPP-adjusted estimates whenever a new price survey is released.