Day-of-the-Week Effects in Subjective Well-Being: Does Selectivity Matter?

Individuals tend to self-report higher well-being levels on certain days of the weeks than they do on the remaining days, controlling for observables. Using the 2008 release of the British Household Panel Survey, we test whether this empirical observation suffers from selection bias. In other words, we examine if subjective well-being is correlated with unobserved characteristics that lead the individuals to take the interview on specific days of the week. We focus on two distinct well-being measures: job satisfaction and happiness. We provide convincing evidence for both of these measures that the interviews are not randomly distributed across the days of the week. In other words, individuals with certain unobserved characteristics tend to take the interviews selectively. We conclude that a considerable part of the day-of-the-week patterns can be explained by a standard "non-random sorting on unobservables" argument rather than "mood fluctuations." This means that the day-of-the-week estimates reported in the literature are likely to be biased and should be treated cautiously.