The Teachers’ Retirement System of the State of Illinois (TRS) requires that some records in the Defined Benefit report be labeled “Deferred” to indicate that employees are being paid for work done in an earlier pay period. It is most often used during the summer, for teachers whose pay is spread across the whole year even though they only work 9-10 months.
You can view how each record is being reported to TRS by opening the Download TRS Gemini File preview. Scroll until you see the Deferred column, which will have a value of either TRUE or FALSE in each Defined Benefit record (SSP records do not use this field).
SchoolInsight sets the Deferred field to TRUE when all records for an employee have 0 Days Paid. All records for that employee will be FALSE if the employee has at least 1 day paid.
See TRS Days Paid (IL) for more information about how the value of Days Paid is calculated.