In Wave 13, respondents with partners that live apart were asked for the contact details of these partners non-experimentally (see Section 10.8). The contact details were collected in a manner similar to questions asked in the Stable Contact Details module. The request made clear that the information would potentially be used to invite their partner to complete the survey, but that no information about the respondent would be given to their partner, other than to say they gave the contact details.
The experiment in Wave 14 was conducted to improve respondents’ willingness to provide partner contact details, employing two potential improvements. In the first condition (sample 2), respondents were again asked to provide contact details for their partner, but with more reassuring wording than what was used in Wave 13. This included wording saying the additional survey would be a one-off short survey. In addition, initial analysis of the Wave 13 data suggested respondents were more likely to provide a physical address for their partner than email, both of which were more likely to be given than a telephone number. The order of these questions was therefore changed in, such that physical address was asked first. Respondents declining to provide details were asked reasons why in an open-text question.
In the second condition, respondents indicating they have a partner living apart were sent information in the interwave mailing about how their partner could participate in the one-off short survey and asked to provide contact details via a webform or by post (sample 3).
For both conditions, respondents who had provided their partners’ contact details in Wave 13 were not asked again.
The randomised allocation for this experiment was allocated at the household level, with half the sample allocated to each group. The variable controlling this experiment is n_ff_ncrrexpw14 on record n_hhsamp_ip (allocation stratified by sampleorig, ff_incentw14, ff_gridmodew13, l_gor_dv, with the latter being recoded to group together values 7&8, 9&10, 2&3, 4,5&6, 1&11):
1 Asked partner details in survey letter
2 Asked partner participation in interwave mailing
The variable affected by this experiment is in the file n_indresp_ip: ncrresp. the variables containing the contact details are not released with the data (questions ncrrequest, ncrtitle, ncrfname, ncrsname, ncrctadd1, ncrctadd2, ncrcttown, ncrctcnty, ncrctpcode, ncremail, ncremail2, ncrcttel1, ncrcttel2, ncrreason).
