Additional data files in some waves

There is substantial variation in the data files produced in Wave 3 from the fertility and partnership history modules, which produce marriage, natchild, adopt and cohab. This is related to the experiments where random subsets of the questionnaire content were presented to respondents (see the experiment Subsetting the questionnaire content).

Generally, we obtain a complete fertility history in the first wave and then only ask about any updates. New entrants to the sample are asked a somewhat shorter version of the module about biological (natural) and adopted children. At IP1, we gave the full fertility history to half of the sample, with the other half receiving the full history at IP2. At IP3, we used the “new entrant/never interviewed” short version. At IP4, the refreshment sample members were all OSMs and so got the full history.

The same logic follows for issues related to marriage and cohabitation from the partnership history module.

Some files have only been produced for a few waves.

• In Wave 4, there is a file related to the Early Bird appointment experiment (See Experiments section) d_admineb_ip.
• Files related to the Measures of Wealth experiment (See Experiments section) in Wave 3 – c_hholdinvest_ip and c_wealth_ip.
• Files d_parstyle_ip and d_chdev_ip and d_breastfed_ip are related to questions about parenting style, child development, and breastfeeding behaviour. They appear in Wave 4. File w_chdev_ip also appears in waves 10 and 11. File e_parstyle_ip is also released in Wave 5. f_breastfed_ip is also released in Wave 6 and j_breastfed_ip in Wave 10.
• File c_wealth_ip is related to types of assets and is released for Wave 3.
• File f_meterreading_ip contains data from the postal/telephone follow-up collection of electricity, gas and odometer readings in Wave 6. See the Experiments section for the description of this experiment.
• File g_timediary_ip contains data from paper time diaries collected in Wave 7 (see Experiments section).
• File i_bufind_ip is an individual level file. It contains the computed monthly income from benefits, pensions, and other unearned income sources which feeds into the Benefit Unit Finances module in Wave 9.
• File i_benefitsum_ip is a benefit unit level file. It includes the computed monthly income of the benefit unit (individuals or couples and their dependent children) from benefits, pensions and other unearned income sources in Wave 9.
• File i_bufinance_ip is a benefit unit level file. It contains data from the Benefit Unit Finances module in Wave 9.
• Files j_nonresch2_ip and j_nonressum_ip and j_nonresid_ip contain data from the ‘non-resident parents and reasons for separation’ experiment in Wave 10. See the Experiments section for the description of this experiment.
• File k_keystroke_paradata contains data captured automatically by the questionnaires script, while respondents completed the HMRC consent module and the HMRC consent follow-up module. See description of paradata files below.
• In Wave 12, there are additional files containing the biomeasures collected.
• File l_experience_ip contains data from one off questions about the respondents’ experience of the interview, such as questions about the kit supplied, whether the respondent would provide blood samples, and the experience of being in IP12.
• File l_hair_ip contains data on the collection of hair during the Nurse interview visit.
• File n_latsurvey_ip contains data collected with a web survey from participants in a Living Apart Together (LAT) relationship and LAT partners for whom we have contact data.
• File n_latsamp_ip contains the sample of participants in a Living Apart Together (LAT) relationship and LAT partners for whom we have contact data invited to the web survey, information about the contact attempts and survey outcome.
• File n_latsurvey_ip contains data from participants in a Living Apart Together (LAT) relationship and LAT partners for whom we have contact data. The data were collected with a web survey of sample members who are in LAT relationships and their partners. The partner’s data is listed under the sample member’s pidp. If they completed the survey a pidp has also been created for them (pidp_sosm).
• File o_bviapp_ip contains additional data on body measurements. IP15 respondents were asked to install the BodyVolume app on their smartphone or tablet (iOS or Android) and use it after the interview to take two photos of themselves. The app used the body outlines along with profile information that the respondent entered in the app (age, sex, height, weight, level of activity) to calculate measures including waist and hip circumference, total body fat, visceral body fat, and lengths of different body parts. See experiment 9.37 Body Volume Index app and body measurements.
• File p_redbook_ip contains heath related data on children under 16 collected from the children’s red books. For details on the experiment associated with this data collection see section 9.44 Asking for child red book pictures. See Benzeval and Payne (2024) for details on the content of this data file.
• File p_shq_results_ip contains data from a mobile app game that tested spatial cognition in IP16. The file contains one observation for every respondent who downloaded the game, see 9.45 Spatial cognition mobile app game. See Coutrot et al (2024) for details on the content of this data file.