A methodological approach to the application of the differences-in-differences model in the expenditure of foods with a high energy content

The increase in health problems derived from the consumption of foods with high caloric content has prompted governments to implement public health policies, with the frontal seal on food products as one of them.The objective is to evaluate the effect of such a policy in urban communities in Mexico through Stata, using microdata from the National Household Income and Expenditure Survey (ENIGH). A working do-file is shown to clean, classify, and describe the variables, regrouping the types of food and using deciles (xtile) according to socioeconomic attributes. A difference-in-differences econometric model is designed to isolate the effect at the regional and temporal levels between control and treatment groups. With loops, 5 regions and 19 selected products are interacted verifying MCO linearity assumptions through the tests: VIF, estat imtest, estat hettest, sktest error, and swilk error, kdensity error, normal. Tables and graphs edited with the outreg2 command are reported, and it is observed that labeling is effective in reducing the expenditure of certain foods and is differentiated according to the region, locality, product, and year.