Unclear rationale for restricting analysis to a filtered subset and consistency of exclusion criteria across universities

Determine the rationale for restricting the analysis to the filtered subset of staff cohorts and establish whether exclusionary criteria (e.g., salary point thresholds) have consistent meaning across different Russell Group universities, especially given that all staff were subject to the national Default Retirement Age prior to 2011.

Background

The Data Report indicates that the filtered dataset covers a subset of staff cohorts, yet before 2011 all staff in Cambridge and the RRG were subject to the national Default Retirement Age. The authors question both the rationale for restricting attention to a subset and whether salary point and contractual criteria are comparable across institutions, which affects the validity of cross-university comparisons.