Can Religiosity be Sensed with Satellite Data? An Assessment of Luminosity during Ramadan in Turkey

Abstract

AbstractSocial scientists have long been interested in how religious beliefs and practices impact and are impacted by socio-political and economic processes. Most recently, scholarly attention has focused on the interplay between religiosity and local actors, events, and institutions. Until now, measures of religiosity have relied heavily on self-reports in surveys, but these cannot always be safely collected and tend to be costly. Even where available, survey-based measures may be too obtrusive and are rarely representative of sub-national units. Here, I propose an inexpensive method that uses satellite imagery to unobtrusively estimate religiosity across small geographic units. I hypothesize that night-lights are affected by the behavior of fasting Muslims during Ramadan, especially in places where daytime activities are otherwise unchanged (i.e., where there is no “day-night inversion”). I explore and confirm the validity of this measurement strategy in the Turkish case, using a series of high-quality surveys and electoral results, representing 973 administrative districts. I conclude with a discussion of the external validity of this method and an overview of the ethical concerns raised by the use of remote sensing to estimate religiosity, in the Muslim world and elsewhere.