Under a four-on-four-off shift pattern, employees work longer (12-hour) shifts for four days in a row, followed by four consecutive days off.
This pattern is mainly used by businesses that require 24-hour cover, with staff working either the day shift or the night shift four days in a row, then switching to the other for the next block of shifts.
A four-on-four-off shift pattern gives staff who work night shifts time to recover and readjust to a more conventional sleep pattern. It also means that they go longer stretches (eight days) without having to work a night shift, so is often preferred by staff who have families or more active social lives.