The Archives and Records Association (ARA) in the UK and Ireland is leading a National Digitisation Project and one of the products of this effort has been published by Find My Past: England and Wales National School Admission Registers and Log-books 1870-1914. (News story at ARA.)
Some of the towns I study are in this first phase of publication, and I'd like to create a Research Plan with a list of all the people in my database who might have been the right ages to be found in this collection.
The school I am most interested in is a County Primary School, but there are also Church of England Schools, Council Schools, Grammar Schools, National Schools, and others, including "Infant Schools". 'Infant' is generally used for newborns now, but the term used to refer to a different age range.
My preliminary search is turning up Admissions log books. How can I find out at what ages children might have enrolled in these schools during this time period?
I know the answer for the USA in my own lifetime and afterwards, and I have some sense of the answer for the USA from reading historical novels, but I haven't researched the question for any periods before that in any country (including my own).
As a rough estimate, I can run a query on my database for anyone who was alive at that date, and exclude all the adults, and let the dataset itself answer the question. But if anyone knows of research guides on the subject or can offer their own expertise, I'd be grateful.
(Afterthought: it might be easier to start with the school-aged children whose names I know from the 1911 Census and simply work backwards from there, rather than running a query. A child born after Census Day in 1911 would be about three in 1914, so their admittance to school would very likely fall outside this data set.)
The admissions registers note whether a student has transferred from another school, which makes these wonderful records to fill in between the census returns for families with school-aged children.
Update: For a description of the records, see the FamilySearch Research Wiki article England Schools under the section "School Records". (This and the other resources in my self-answer were found after Judith posted her answer.)