Bit of a controversial idea this one but I’m going to put this out there: is using a questionnaire to gather data at all helpful in the quest to measure behaviour? Lots of psychologists use this research method, probably because:
a) it’s quick to fill in (usually, although I wouldn’t recommend that you start filling in Eysenck’s personality inventory unless you have the whole day to spare!)
b) easy to produce and to replicate, particularly in these days of the world wide web and SurveyMonkey
c) quantitative data is generated which can be fashioned into handy little graphs and neat percentages
d) lots of people are aware of and regularly fill in questionnaires so there’s no danger of participants scratching their heads and muttering, ‘What is this strange and unusual item before me?‘
But the above reasons are not really enough to justify the use of a measure that is so darned unscientific, imprecise and prone to the mood of the person filling it in. Social desirability bias, outright lying, deluding oneself, trying to mess with the researcher’s results, not understanding or misinterpreting questions: none of these can ever be fully ruled out when analysing questionnaires. I rest my case: questionnaires are a bit of a cop-out in terms of psychological research. Now, would you like to fill in a questionnaire to indicate your level of agreement with this opinion….