Factors Affecting Measurement Error in Mobile Phone Interviews

Introduction Imagine a survey question that asks, “How many hours do you spend watching TV in a typical week?” A respondent may answer “16”. Whether that is the ‘correct’ answer depends on what exactly the researcher intended the question to measure. The respondent may have come up with his answer by thinking along the following lines: “The TV is on for about two hours each evening, so that’s 14 hours, plus I usually watch the sport for a couple of hours on Saturday afternoon, so that makes about 16 in total.” But maybe the researcher only had in mind time spent actually paying attention to the content of a TV broadcast, so having the TV turned on while devoting one’s attention to something different should not be counted. If, during the two hours each evening that the respondent’s TV is on, he is also eating dinner and talking to his children, then he may only be paying attention to the TV for half of that time. So, in the researcher’s terms the ‘correct’ answer would have been nine hours. There may be many people in the survey sample who, like this respondent, have included in their response to this question time that the TV is switched on even if they are not really paying attention to it. This will result in the researcher over-estimating the time people spend attentively watching TV. This error in estimation could have important consequences.