Data Item Ref: 55. Pay Period. Options allowed are 1-53 determined by the payment date and pay frequency. Input options allowed are 1-53 where payment frequency is weekly, 1-27 for fortnightly, 1-24 for twice monthly, 1-12 for monthly, 1-14 for week-based monthly, 1-14 for four-weekly, 1-4 for quarterly, 1-2 for bi-annual, 1 for annual and 1-52 when payment frequency is other. Where an employee is on a week 1 basis, the pay period that would be applied by software were it not for week 1 basis should be reported (required from 2020 onwards).