Child development up to the age of 2 is a key determinant of child and adult health. However, directly and regularly measuring physical health is invasive and time consuming for families, and costly for the Study. We therefore wished to investigate whether it is possible to collect such data from administrative records parents should hold for the child in the ‘red book’.
The experiment asked respondents with children under 16 in the household to upload a photo or provide red book information. Based on IP15 data on household composition, half were allocated to being asked to provide photos online ahead of the interview, this request was sent to them four weeks before the interview invitation. The other half were informed in their advanced letter they would be asked within the interview. Those in the pre-interview group that did not provide the photo or information were asked to do so in the interview along with the second group. Similarly, any new parents identified in the IP16 interview were asked to provide a photo or information within the interview. Parents completing the interview by telephone were asked to provide data as part of the interview.
Those with children under one years old were asked to upload a picture, and if not, report from the red book, the height and weight of children at 6-8 weeks or the closest date to that. Respondents with children aged one or older were asked for these for when the children were one year old or the closest time to that. Respondents providing these data were given a conditional £2 incentive.
Eligible households were randomised to pre-interview or during-interview requests in equal proportions. The controlling variable is in file p_hhsamp_ip:
ff_redbookw16 (1/2 each of those with children under 16 at IP15, allocations stratified by ff_kids015w16 ff_gridmodew16 ff_incentw16 ff_perksw16 sampleorig)
1 = Pre-interview request
2 = In-interview request
This experiment affects the following variables in file p_indresp_ip:
rbletter, rbdone, rbnotall, rbwill96, rbentint96, rbmeasure, rbothmeas, rbnotused1, rbnotused2, rbnotused3, rbnotused4, rbnotused5, rbnotused97, rbnotusedoth_code, nfrbnum
It also affects all variables in the file p_redbook_ip. This is a child level file, although on a few occasions both parents entered data for the same child, which has been retained. The following are documented in the IP16 questionnaire:
rbwill, rbwpimp, rbwoimp, rbhimp, rbwkmet, rbwogmet, rbhmet, rbusedwebtel, rbusedin, rbdated, rbdatem, rbdatey, nfrbdoby, redbooktype
The p_redbook_ip file contains additional variables that are not documented in the IP16 questionnaire. For information on these, see Benzeval and Payne (2024):
rbtwins, rbwhich, dobmatch, rbentint, rblength, smokeexp, namematch, rbsomewho, weighting, rbbooktype, rbfollowup, rbheadcirc, weightinkg, birthweight, rbimgsource, rbnotselctd, weight_g_dv, height_cm_dv, rbvisitweeks, uploadedpage, weight_kg_dv, breastfeeding, datesagematch, birthweighting, breastfedweeks, rbdetsource_dv, birthweightinkg, nodateofcontactreason
