About 1,000 small schools will be included in league tables this year for the first time as the Government changes the threshold for inclusion from 11 to just six pupils.
The decision has angered headteachers who are concerned that the statistics will be misleading and could identify individual pupils.
Currently, schools where 10 or fewer pupils have taken the tests at the end of Year 6 do not have their results published. A proposal to include the value-added scores of small schools in the tables in 2003 was not taken forward after consultation.
Now the Government has said it has reviewed the policy and decided that it can lower the limit. A statement from the Department for Education said: "This will mean that we can now show data for a number of small schools who have previously been frustrated that their results haven't been published."
But not all headteachers agree they have been frustrated over the suppression of their results.
Frank Green, head of 71-pupil Cockerham Parochial CofE Primary in Lancaster, described the change as "totally stupid".
"If you look at a realistic sample of children, I wouldn't even go as far as 10 or 11; I would have no less than 20 published.
"Our results are not bad; we are among the top schools in Lancashire. I could say it would be useful for me for the results to be published because they are good, but I think the opposite - a small school in a rural situation is very different from a school in the centre of Salford. There is no comparison."
Judy Goldsmith, head of 70-pupil Guilden Morden CofE Primary in Cambridgeshire, said: "My governing body and I have just sent a letter to (education secretary) Michael Gove saying that he must reconsider the treatment of small schools which are vulnerable when decisions are made on percentages, but this makes a situation which is already dreadful worse.
"You end up having a conversation about 50 per cent of girls getting level 5 but no boys - but you are only talking about two girls and one boy, so it is not statistically valid at all. And it would be so easy to identify an individual child. Parents would very easily work out which two children didn't get a particular level."
Bill Goodhand, chair of the National Association for Small Schools and governor of Welbourn Primary in Lincolnshire, said that the publication of results would be generally positive.
"But individual schools might be hesitant because from time to time you get a statistical blip where a child has struggled," he added. "The results would need to have some warning on how they are interpreted."
The DfE said the change would not alter its policy on floor targets, which are not applied to cohorts of 10 or fewer pupils.
As well as the change to which schools have their results published, more information will be made available on all schools. These include the number of low, medium and high-attaining children at age seven and how they have progressed by age 11; the number of children on free school meals; and the number of children who are looked after by the local authority.
The changes are part of the Government's drive for greater transparency through publishing more data. It has also taken account of an inquiry into assessment at key stage 2 led by Lord Bew, who recommended including measures such as three-year rolling averages. These are being considered for 2012.