The survey was offered both online and as a paper version which could be returned by post.
The first two invitation letters provided the link/unique passwords to the online survey and a paper questionnaire was offered at mailing 3 (alongside a repeat of the online log-in details). Mailing 4 provided a final reminder with details of the online log in details included again.
Although the paper questionnaire was only sent unprompted at Mailing 3, participants could request a paper questionnaire after any of the mailings. In the final dataset for November 2023 – November 2024, 76.0% of the completed surveys were online and 24.0% were on paper.
The paper questionnaire is 16 pages long with 42 questions and involves some simplification of the online version.
For example, it is not possible to offer the complete list of activities which can be shown online. This is because for the online questionnaire, activities are grouped into categories and respondents can click to see a drop down of the activities within each group. This allows a larger number of activities to be presented than on the paper questionnaire.
In addition, more complex questions (such as those asking which settings activities take place in) are not included on the paper questionnaire, since on the online version only the settings tailored to each activity are shown and this sophistication is not possible on the paper questionnaire.
The following section shows the survey content for each phase and mode and so highlights where data are not available from the paper questionnaire.
As well as allowing the inclusion of more complex questions and options than the paper questionnaire, the online questionnaire also allows for checking of responses. For example, unexpectedly or implausibly high responses for number of sessions per month or length of session can be checked online, giving the respondent a chance to correct their answer.
It is also possible to query logical inconsistencies such as an answer of zero adults in their household and to design questions to prevent people selecting multiple answers on questions where only one answer is required (e.g. gender).
On an online survey, it is also possible to prevent people accidently missing questions. This means that the data from the online survey can be considered more complete than those from the paper questionnaire.
An ongoing challenge for the survey is increasing the percentage of questionnaires completed online.
Efforts to maximise the online response to the survey have been made by offering a device agnostic online questionnaire. This means it can be completed on a desktop or laptop computer, a tablet or a smartphone.
For simpler questions the format is the same on any device, but for more complex questions (for example, grids) the presentation is automatically changed according to the device on which it is completed.
The drop-down response lists (for example on activities and ethnic groups) work equally well on all types of device.
The in-house testing of the online questionnaire involved testing on a range of devices including laptops, desktop PCs, standard and mini tablets (on devices with android, iOS, and Linux operating systems), and the most popular types of smartphones (including the latest and older models). It also involved thorough testing on the most popular browsers (Internet Explorer, Chrome, Firefox and Safari).