4.1.3. Measurement errors
Measurement error occurs when the recorded answer to a question deviates from the true answer. The risk of such error is increased by an imprecise or wrongly formulated question. These errors can also occur in face to face surveys, if the interviewer influences the respondent (interviewer bias). Moreover, a survey is always declarative, so the respondent can voluntarily give a wrong answer if the question is in some way sensitive.