Ben Page, director of MORI, told FE Focus that to get a satisfaction rate of around 90 per cent, as did the Learning and Skills Council in a study of learner satisfaction last autumn, researchers either used questionable methodology or interpreted results too loosely.
His criticisms came this week as the LSC planned to publish the full results and methodology on the web. A spokesman said: "We are hoping colleges will use the same methodology across the sector to give a consistent picture."
The survey was given considerable publicity by national organisations including the Association of Colleges, to counter accusations that further education was under-performing.
Of the 25,000 students and trainees in work-based centres surveyed, 11 per cent said they were dissatisfied. The majority said they were "fairly satisfied", "satisfied" or "very satisfied".
Mr Page said he did not question the accuracy of the responses. "However, you cannot group together groups who say they are satisfied, fairly satisfied and very satisfied and get a good measure."
His criticisms extend to similar approaches by the NHS, which record very high patient satisfaction levels. He will analyse approaches to surveys and "the art of measuring customer satisfaction" when he speaks at the Learning and Skills Development Agency's conference in London next week.
"The problem is that learners nearly always seem satisfied," he said. MORI has several questions about the survey: If they are delighted, why do so many young people drop out? What do the different levels of satisfaction mean?
"If your survey shows 90 per cent, you are probably not measuring the right things. The most significant measure of true satisfaction may only be the 'very satisfied' group."
The LSC spokesman said the survey was done by its statisticians and NOP World. He denied the results were unreliable. "We use a seven-point scale which shows 23 per cent are satisfied, 40 per cent fairly satisfied and 26 per cent very satisfied. It would be stupid to lump them together. We do not do that but cannot speak for others."