Pupil mobility and school disruption

Pupil mobility between schools is something to be encouraged if it facilitates the efficient matching of pupils to provision, but discouraged if turnover imposes costs on other pupils through disruption in teaching and learning. With this in mind, we consider the externalities imposed by entrants on the achievements of incumbent pupils in English primary schools. We find that immobile pupils who experience high pupil entry rates in their yeargroups (la US "grades") progress less well academically between ages 7 and 11 than pupils who experience low mobility in the same school. The disruptive externalities of mobility are statistically significant, but quite small in terms of their educational impact. An increase in annual entry rates from 0 to 10% (a 4 standard deviation change) would set the average incumbent pupil back by between 1 and 2 weeks, or about 5% of one standard deviation of the gain in pupil achievement between ages 7 and 11