School absence trajectories and their consequences for achievement

In this study, we examined the joint trajectories of authorised and unauthorised absences from first year of primary to the end of secondary school, and their consequence for educational achievement. Our sample consisted of linked data from the Millennium Cohort Study and the National Pupil Database in England (N=7093). Employing k-medians clustering for longitudinal data, we identified seven distinct absence trajectories. Five of these clusters had very low levels of unauthorised absences but different levels and dynamics of authorised absences (constantly low, constantly moderate, decreasing, slightly increasing, dramatically increasing), while two clusters were characterised by moderately and dramatically increasing unauthorised absences in the last years. Next, using a regression-with-residuals approach to adjust for time-varying confounders, we found that absence trajectories had significant consequences for pupils’ achievement, with a large effect size. The largest disadvantages appear for pupils with dramatically increasing unauthorised absences followed by dramatically increasing authorised, and moderately increasing unauthorised absence trajectories. These pupils were between 25 and 40 percentage points less likely to obtain 5 GCSEs. Even low to moderate absence trajectories were significantly detrimental to achievement. Our findings suggest a need to pay equal attention to all forms and levels of absences throughout the educational life course.