Each year we ask respondents a set of core questions, but questions which ask about aspects of people’s lives that are not likely to change frequently, are asked less often.
This is done to make sure the interviews are not very long (so reduce respondent burden) and that the questions are meaningful and relevant. For example, it is not sensible to ask someone’s country of birth every year as that will not change over time.
Initial conditions questions
Initial condition questions are asked only once, generally the first time someone is interviewed as these are not expected to change, e.g., country of birth, date of birth. These questions may not be asked in Wave 1 for everyone in the sample, as not everyone joins the survey in its first wave. Those who join the household after the first wave will be asked in the wave they join. Similarly, when new samples are added these questions are first asked in that wave, e.g., these initial conditions questions were asked of the IEMB sample in Wave 6 (2014-2016) when the sample was first introduced. To make it easier to use, we have gathered the answers to these initial conditions questions, in whichever wave they were answered, and put them together in one individual level file xwavedat.
Rotating modules
Rotating modules refer to questions that are asked every few years as they are expected to change less frequently, such as a respondent’s wealth, friendship network, personality traits and so on. This is done to reduce respondent burden. To fill data gaps between the rotations, some researchers and analysts use a respondent’s data from the nearest rotation. However, this approach may not be appropriate in all research applications and is left for the researcher to determine.
Event triggered questions
Some questions are triggered by changes in individual circumstances. For example, questions about retirement planning such as expected age of retirement (ageret) are asked when the respondent is aged 40, 45, 50, 55, 60 or 65 and still not retired.
Specific questions about one-off global events are added to the questionnaire in the relevant waves to expand the study’s research possibilities. For example, questions about the 2012 London Olympics (in Wave 4 (2012-2014) and Wave 5 (2013-2015)), or experiences during the Covid19 pandemic (such as Covid19 symptoms Pcovidsymp or the amount of furlough payment received Jsseissam in Wave 11 ( 2019-20) and Wave 12 (2020-21)).
Other questions are triggered by specific global events, such as questions about the voting behaviour during the last General Elections (Vote8) are asked of respondents interviewed in the months after the General Elections (e.g., Waves 11 and 12) following the general election in December 2019, Waves 9 and 10 during June 2017 – May 2018 following the general election in June 2017).
