In the same spirit as my earlier posts on OSM coverage of shops and healthcare facilities, I've now had a crack at estimating the number of schools that can be found on the map. I've used Department for Education figures to get an estimate of the number of schools we should find in each local authority area in England. These are pretty comprehensive. They include independent schools as well as state funded primary and secondary schools. They also include some nursery schools (basically those receiving state funding), special schools (for children with specific educational needs) and pupil referral units (for children excluded from other schools).
By comparing these figures with the number of features in OSM that are tagged as a school I get an overall figure for coverage of schools in England around 75% - which looks pretty good. Local authorities that have particularly thorough coverage include Cambridgeshire, York, Sheffield, Hartlepool, and Bath. There's a patch around Barnsley, Doncaster, and Rotherham where coverage is low.
Some of these figures look too good to be true. I suspect that my collection of OSM features is too crude, and that this results in some double counting - perhaps as a result of the way campuses have been tagged. That's going to take a while for me to investigate, but meanwhile, this is what the first iteration looks like.