“In many cases working hours follow a well-defined schedule, which can be changed only in exceptional circumstances (child sick, unexpected family event, etc. In situations with non-negotiable working hours, the degree of predictability becomes a determinant element” (Le Bihan & Martin, 2004, p. 575).
Le Bihan, B., & Martin, C. (2004, December). Atypical working hours: Consequences for childcare arrangements. Social Policy and Administration, 38(6), 565 - 590.