We use data from the Expenditure and Food Survey (EFS), which is administered every year in the UK. The annual sample includes between six and seven thousand households. For each household, an initial interview collects detailed demographic information. Immediately after the interview, each household member starts a expenditure diary, in which they record everything they buy during the next fourteen days. Diary expenditures are aggregated to “diary weeks” in the data, for reasons of confidentiality, resulting in two seven-day aggregates of expenditure for each individual. Importantly, the timing of the EFS interview, and the subsequent diary recordings, is random during the sample year. Figure 1 illustrates the resulting.
