Asking pupils if they lie on a regular basis seems a doomed undertaking: either they will fabricate their answers, or you will discover that you are working with a group of compulsive liars.
Nonetheless, this is exactly what Mike Hobbiss and his Year 13 pupils decided to do.
Mr Hobbiss, head of psychology at Bolton School in Lancashire, was approached by a local educational psychologist, who wanted his pupils to take part in a study into teenagers' lying habits.
Instead, Mr Hobbiss suggested that his A-level psychology pupils - the potential lying subjects of the study - conduct it themselves.
"It's increasingly hard for pupils to perform their own research investigation," Mr Hobbiss said. "Quite a lot of what's covered in the A-level syllabus are things like memory capacity, which you teach in universal terms.
"But lying is a very personal subject. It made them consider their own ideas and their own environment."
Seventeen-year-old Joel Harrison-Hirst was less circumspect. "How are you going to do a study about lying?" he said. "People could just lie."
To tackle this, the pupils drew up anonymous questionnaires, to be distributed to 50 sixth-formers at five different schools. Two schools, including Bolton, were high-achieving, one was in special measures and one was failing.
Pupils asked a series of questions, designed to highlight the motives behind different types of lies. For example, aware that lies are often told to avoid punishment, the pupils asked: "If you had been smoking and smelled of cigarette smoke, would you blame it on someone smoking near you?"
The responses revealed that certain lies were more common in certain schools. Ninety per cent of pupils in the high-achieving girls' school said they would tell a classmate she was popular, even if she was not. In all other schools, a maximum of 40 per cent of pupils told this lie.
Meanwhile, self-aggrandising lies were far more common in low-achieving schools. These pupils were significantly more likely to claim that they knew a celebrity than their high-achieving counterparts. "Possibly the kids at the best schools actually do know famous people," Mr Hobbiss said.
Pupils at the failing schools were also the only ones who said they would falsely claim that a classmate had been abused. But the teenage psychologists have resisted drawing unsubstantiated conclusions from this.
"We don't really know the people," said 18-year-old Oliver Smith. "Something about their situation makes those lies more common, but I don't want to fall into prejudice and stereotyping."
Joel, meanwhile, remains sceptical. "I think everyone tells manipulative lies like that now and again," he said. "But maybe they wouldn't admit it to themselves."
However, he was impressed by respondents' general truthfulness. "I was surprised how much people lie," he said. "But I suppose it makes me look at people in my year a bit differently."
Oliver agrees. "Lying is more common than I thought it was, so I pay more attention to what people say now," he said. "But I probably tell the same lies, but without realising."
Nonetheless, their classmate, Michael El Gawly, argues that the results are not a reflection of pathological teenage dishonesty. Instead, the 18-year-old points out that school itself encourages certain types of lying.
"People lie out of boredom in school," he said. "And teenagers have different responsibilities from adults. It's one thing to lie about having done your homework, out of fear of punishment. It's different if an adult lies to the police for the same reason. The same lie might have more serious consequences for adults."
THE TRUTH IS TELLING ...
- Why do pupils lie?
Social reasons - 44%
Fear of punishment - 41%
Self-aggrandisement - 30%
To protect friendsloved ones - 39%
Boredom - 20%
Manipulation - 10%
- How many would tell someone they were popular, even if they were not?
Girls' grammar - 90%
Failing school - 40%
School about to merge - 20%
Boys' grammar - 10%
Co-ed grammar - 0%
- How many would say they knew a famous person, even if they did not?
Failing school - 80%
School about to merge - 80%
Girls' grammar - 1%
Other schools - 0%
- How many would falsely say someone they knew had been abused?
Failing school - 2%
School about to merge - 2%
Other schools - 0%
- How many have ever apologised for telling a lie?
All schools - 100%.