Academic achievement in England is strongly impacted by class, with those of a higher socioeconomic status (S.E.S.) more likely to achieve than than those of a lower S.E.S. (Clifton & Cook, 2012). These gaps between students can be seen between students as early as three years old (Feinstein, 2003) and continue to widen as the children age (Feinstein, 2004). One of the historical measures to reduce these inequalities is ability grouping. Students are placed into groups based on their test scores for certain subjects so they can be taught with their peers of similar ability. ‘Streaming’ (called ‘tracking’ in the US) divides students into groups based on their test scores across all/most of their subjects, meaning they stay with the same students across those subjects. This is similar to ‘banding’. ‘Setting’ occurs when students are put into ability groups for specific subjects that are not necessarily consistent across subjects e.g. a student could be placed in top set for maths but middle set for English (Francis et al., 2017). Data on the prevalence of ability grouping is inconsistent but the evidence suggests it is prevalent in secondary school and to a lesser extent primary school in the U.K. (Dracup, 2014). It is becoming more common in the U.S. after a drop in popularity during the 1990’s (Steenbergen-Hu, Makel, & Olszewski-Kubilius, 2016).