Detecting Problems in Survey Data Using Benford's Law

Abstract

It is 15:00 on Friday in Nairobi. Do you know where your enumerators are?? Good quality data is paramount for applied economic research. If the data are distorted, corresponding conclusions may be incorrect. We demonstrate how Benford's law, the distribution that first digits of numbers in certain data sets should follow, can be used to test for data abnormalities. We conduct an analysis of nine commonly used datasets and find that much data from developing countries is of poor quality while data from the US seems to be of uniformly better quality. Female and male respondents give data of similar quality.

Keywords: Benford's law, first-digit phenomenon, relative frequencies, data errors, survey quality

JEL Classification: C10, C24