Last year, 75 per cent of pupils at Moorlands junior school in Sale, Greater Manchester, reached level 4 in English, and 73 per cent in maths - the same level as the national average.
But headteacher Jane Hiller says the figures are not an accurate reflection of how her school performs.
The 200-pupil primary has a unit for 24 children with moderate learning difficulties who might be working towards level 1 by age 11.Their results are included in the school's final percentage of pupils reaching level 4.
Among the mainstream pupils 86 per cent reached level 4 in English, and 84 per cent in maths.
Ms Hiller says: "There is this odious comparison with 'similar' schools which is done on the basis of free school meals, but if you have a unit of 24 children with moderate learning difficulties, then they are the significant factor - not free school meals.
"We got 75 per cent, fair enough. But we do have eight children who live nowhere near the school who have come to us for a special reason. I don't wish to negate their results, but they are never going to get level 4.
"I never want to say children with special needs haven't achieved - they have achieved very well - but there should be a different measure for them.
"If you are under pressure to get good results, there is pressure to do revision until you're blue in the face. You need the strength to resist it. It is a little relentless. I am sure results can't keep on and on going up - they just can't."