A Comparison of Approaches for Identifying Minimum Wage Workers: Direct Question Versus Administrative Earnings Data
比较了使用行政收入数据和直接调查问题两种方法识别最低工资工人的差异，发现方法选择会影响对最低工资工人特征和结果的研究结论，并提出了结合两种方法的改进估计。
ABSTRACT The ability to identify minimum wage employees is essential for minimum wage research. When the minimum wage is set at an hourly rate, such as in Ireland, Germany, the United States and the United Kingdom, researchers often combine monthly or weekly earnings data with self‐reported hours worked to calculate an hourly wage to determine if a worker is on minimum wage. This may lead to misclassification, whereby higher paid employees are misclassified as minimum wage employees or vice versa. An alternative, but less common, approach for identifying minimum wage employees is to use a direct survey question. Ireland is the only country in Europe whose labour force survey includes both linked administrative earnings data and a direct minimum wage question, thereby facilitating a comparison of both approaches. When studying the incidence, characteristics and outcomes associated with minimum wages, we show that the choice of approach (administrative data vs. survey question) can produce different results. We discuss the limitations of each approach when it comes to implementing difference‐in‐differences analysis to study the impacts of a minimum wage increase. We then combine useful features from both approaches to come up with a difference‐in‐differences estimate that overcomes some of the limitations that exist when using either approach on its own. We argue that the addition of a standardised minimum wage question in labour force surveys across Europe would allow researchers to provide more robust estimates on the impacts of minimum wage changes, while also facilitating cross‐country minimum wage research.