This much I know about...how Progress 8 might just be a proxy measure for poverty and EAL

I have been a teacher for 29 years, a Headteacher for 14 years and, at the age of 53, this much I know about how Progress 8 might just be a proxy measure for poverty and EAL. It is worth pointing out the bleeding obvious. When we were inspected back in October, I failed to point out to the inspection team that our cohort is 95%+ White British, the sixth worst performing ethnic group in England at Key Stage 4 in 2017 in terms of progress (P8 score: -0.14). The five ethnic groups whose P8 score was worse than White British were:  traveller of Irish heritage (-1.13); Gypsy/Roma (-0.80); white and black Caribbean (-0.33); black Caribbean (-0.23); Chinese unclassified (-0.41). With the average P8 score for disadvantaged students being c. -0.4, then it is not hard to see that if your cohort is overwhelmingly White British and disadvantaged, then, according to the data, the challenge to secure a positive P8 score is huge. Gorton vs York revisited. A few weeks ago I queried why a disadvantaged child in Gorton, Manchester, makes better progress than his or her York counterpart at every stage of his or her education. It prompted the Principal of Manchester Enterprise Academy in Wythenshawe in Manchester, James Eldon, to contact me. He sent me two graphs. The first graph plots the 2017 outcomes of a number of schools whose cohort is 0-5% English as an Additional Language. The Y-axis measures the schools’ Progress 8 scores and the X-axis measures the percentage of “Pupil Premium Ever 6” students: The second graph plots the 2017 outcomes of a number of schools whose cohort is 35-40% “Pupil Premium Ever 6”. The Y-axis measures the schools’ Progress 8 scores and the X-axis measures the percentage of EAL students: A school’s Progress 8 scores certainly measures its students’ academic progress; after looking at these two graphs, James Eldon and I wonder whether the Progress 8 score also measures the levels of poverty and EAL within a school’s student body.