model.frame.default(x, design$variables, na.action = na.pass)

model.frame(x, design$variables, na.action = na.pass)

in paid work or self employed - full time
in paid work or self employed - part time
unemployed
intending to look for work but prevented by temp sickness
permanently sick or disabled and not able to work
looking after the home or family full time
in full time education
doing something else
caring

higher degree in addition to first degree