If you were a member of the scheme before 31 March 2014 you built up membership in the scheme, which is used to calculate your pension (see How much will my pension be?).
Membership is the calendar length of your service, but if you were part time this is pro rated by your part time hours.
For example:
A member worked whole time for 2 years. They built up 2 years membership of the scheme.
If the member had worked half time (18.50 hours a week out of a standard 37 hours) for the same 2 years, they would have built up the following membership:
2 years x 18.50 / 37.00 = 1 year
If a member had worked term-time, their membership will be reduced in accordance with the number of paid term-time weeks for which they are employed. For example, if a member works half time (18.50 hours a week out of a standard 37 hours) for 45.22 paid weeks a year, their membership over 2 years would be calculated as follows:
Firstly, reduce contractual hours by paid term-time weeks: 18.50 x 45.22 / 52.14 = 16.04
Then their membership is calculated as follows:
2 years x 16.04 / 37.00 = 316 days
Membership is calculated on a day to day basis for benefits that built up before 31 March 2014, so any earlier full-time service will always be protected