The following is an excerpt from a working (i.e. unpublished) academic paper. Which empirical research strategy is being used here?

"We develop a non-cooperative bargaining model with incomplete information linking dowry payments, domestic violence, resource allocation between a husband and a wife, and separation. ... Our empirical analysis exploits the introduction of amendments to the Dowry Prohibition Act between 1985 and 1986 as a natural experiment, and consists of two main parts. Using data from the Rural Economic and Demographic Survey, we first confirm that the amendments were successful at reducing dowry payments (Alfano, 2017). Next, we test the predictions of our model using data from the National Family Health Survey. Since the Dowry Prohibition Act (initially introduced in 1961) and its amendments do not apply to Muslims, we exploit variation in religion and year of marriage to identify the effect of the reforms..."