The vectors Z m and Z f contain control variables (other than age functions) such as education level, presence of children, area of residence dummies, and a dummy for whether the time use diary was collected on a weekend day.
The diaries include a sketch of dummy figures deployed by British troops in a tactic called "Chinese attacks" after deception techniques developed by Chinese military strategists.
As far as the other covariates go, we control for education dummies, the number of children living at home, area of residence dummies, seasonal dummies, and for the day (weekday or weekend) on which the activity diary was collected.
To investigate this possibility, I estimated regressions for shopping time in the full sample of diaries, including among the regressors a binary variable equal to one if the diary pertained to a day off, and an interaction term between this dummy and the dummy for working split shifts.
Other controls: quadratic polynomials in age 60 interacted with the age ≥ 60 dummies; partners' education dummies; a dummy for any child still living at home; area of residence dummies; seasonal dummies; and a weekend diary dummy.
Other controls include partners' age polynomials interacted with the dummies for being aged 60 and above; partners' education dummies; a dummy for any child still living at home; area of residence fixed effects; season of the year; and weekend diary dummies.
