Notes: This table is discussed in Section 5 (rows 1–4) and in Section 7.2 (rows 5 and 6). Results obtained from 12 separate regressions. Rows 1, 2, 3, 4, 6 and 9 use the main sample of 6,815,997 student-subject observations. Row 5 uses a reduced sample of 2,041,902 student-subject observations who attended primary schools with cohort sizes of less than 31. Row 7 is estimated using a sample of 452,088 student-subject observations from students who had no primary peers in secondary school. Row 8 uses a reduced sample of 6,235,806 student-subject observations from students who did not attend a secondary school classified as specialist. The dependent variable is by-cohort-by-subject percentilised KS3 test scores. Student characteristics are ethnicity, gender, and Free School Meal Eligibility (FSME). SSC effects are fixed effects for each school-by-subject-by-cohort combination. The second column presents corresponding estimates for rank effects within student only. Standard errors in italics and clustered at the secondary school level. Significance levels *** 1%,** 5%, * 10%.