On the danger of priming in surveys

The responses to questions can also be influenced by what has been asked beforehand, a process known as priming. Official surveys of wellbeing estimate that around 10% of young people in the UK consider themselves lonely, but an online questionnaire by the BBC found the far higher proportion of 42% among those choosing to answer. This figure may have been inflated by two factors: the self-reported nature of the voluntary ‘survey’, and the fact that the question about loneliness had been preceded by a long series of enquires as to whether the respondent in general felt a lack of companionship, isolated, left out, and so on, all of which might have primed them to give a positive response to the crucial question of feeling lonely.

Excerpt from: The Art of Statistics: Learning from Data by David Spiegelhalter