Appendices for Food and You 2 Wave 4 Technical report

List of appendices

The online questionnaire has been included as an Appendix to the technical report but is available as a separate PDF and a table of methodological differences between waves has been presented overleaf. 

The rest of the documentation (listed below) will be uploaded onto the UK Data Archive:

PDF

View Food and You 2 Wave 4 online questionnaire as PDF(Open in a new window) (405.49 KB)

Food and You 2 Wave 4 postal questionnaires

• England and Wales Eating Out version
• England and Wales Eating Out version in Welsh
• Northern Ireland Eating Out version
• England and Wales Eating at Home version
• England and Wales Eating at Home version in Welsh
• Northern Ireland Eating at Home version

Food and You 2 Wave 4 invitation and reminder letters

• invitation letter 
• first reminder
• second reminder
• final reminder

Food and You 2 Wave 4 full SPSS data
Food and You 2 Wave 4 SPSS user guide
Food and You 2 Wave 4 full data tables (and user guide) for England, Wales and Northern Ireland combined 
Food and You 2 Wave 4 individual country data tables (and user guide) for England, Wales and Northern Ireland

Methodological differences between waves 1-4

Table 17 compares the differences between waves 1-4 in sample size and participaton rates. The largest sample size was in wave 1 (21,053), dropping to 13,922 in wave 2 and remaining at 14,115 for waves 3 and 4. As up to two adults per household can participate the number of returns overall is always higher than the number of households participating. The number of returns overall is shown in the table. In Wave 1, 6,408 households participated; 3,955 did so in wave 2; 4,338 in wave 3 and 4,026 in wave 4. The highest response rate was achieved in wave 3: 30.7%. 

Table 17: Comparing differences between Waves 1 to 4 in sample size and participation rates between Waves 1 to 4

Wave	Main sample size (addresses)	Number of returns overall	Overall response rate
1	21,053	9,319	30.4%
2	13,922	5,900	28.4%
3	14,115	6,271	30.7%
4	14,115	5,796	28.5%

The number of households that participated also varied across the waves:

• Wave 1 had 6,408 households
• Wave 2 had 3,955
• in wave 3 there were 4,338
• in wave 4, 4,026

The average length of the online questionnaire was different in each wave:

• Wave 1 was 29 minutes and 58 seconds
• Wave 2 was 36 minutes and 27 seconds
• Wave 3 was 30 minutes and 13 seconds
• Wave 4 was 37 minutes and 14 seconds

Table 18 shows that in waves 1, 2 and 4 two versions of the postal questionnaire were fielded whereas there was a single version in wave 3. The fieldwork periods for waves 1 and 3 and for waves 2 and 4 were broadly similar with the first being conducted in Spring/Summer and the latter in the Autumn/Winter. Over half of all non-responding households were sent the final reminder mailing in all countries in each wave.

Table 18 Comparing differences between Waves 1 to 4, for postal questionnaire versions, fieldwork timing and mailing sample

Wave	Number of different versions of postal questionnaires for each country	Fieldwork period	Proportion of available sample sent final mailing
1	Two (Version A and Version B)	29th July to 6th October 2020 (about 10 weeks)	100% of non-responding households in Wales and Northern Ireland.  50% of non-responding households in England
2	Two ('Eating Out' and 'Eating at home')	20th November 2020 to 21st January 2021 (about nine weeks)	100% of non-responding households across the sample.
3	One (with different questions in Northern Ireland than for England and Wales	28th April to 25th June 2021 (about eight weeks)	66.6% of non-responding addresses across the sample
4	Two ('Eating Out' and 'Eating at home')	18th October 2021 and 10th January 2022 (about 12 weeks)	100% of non-responding households across the sample

Questionnaire development

In Wave 1 a prolonged period of questionnaire development took place which involved an extensive review of questions from previous FSA surveys (Food and You and Public Attitudes Tracker). After all relevant questions were compiled a workshop with the Food and You 2 advisory group was held to discuss key priorities for the questionnaire. This was followed by a second workshop with key internal stakeholders to discuss their priorities for the questionnaire and provide Ipsos with direction regarding questionnaire content. 

Following this, draft questionnaire modules were compiled based on questions from previous FSA surveys. Numerous alterations to the wording, ordering, format and content of the questions were made in the process based on survey design best practice, with additional questions designed based on stakeholder needs. The questionnaire development stages for Waves 2, 3 and 4 were much shorter as core questions and materials had been developed in Wave 1.  

Cognitive testing

Ahead of each fieldwork wave, cognitive testing was conducted to examine participant comprehension of new or potentially challenging questions. Participants for cognitive testing were recruited from Ipsos MORI’s iOmnibus recontact database and for wave 2 onwards, via an external Ipsos approved supplier. In Wave 1, 26 cogntive interviews were completed. In Wave 2, 14 interviews were completed, and 20 interviews were conducted when developing the Wave 3 questionnaire, and again for Wave 4. 

Usability testing

Prior to Wave 1 fieldwork, usability testing was also undertaken to identify areas where improvements could be made in the form and format of the questions on the online survey across different commonly used devices (for example, mobile phone, tablet, computer). Interviews were conducted over online video conferencing software, with interviewers observing participants journey through the online questionnaire (using screen share technology) and asking questions where relevant. Eleven interviews were undertaken at this stage. This helped identify formatting and layout issues with the online questionnaire which were amended ahead of the pilot survey. Usability testing was not conducted again ahead of Waves 2, 3 or 4 as the online questionnaire took the same format as the Wave 1 questionnaire.

Pilot

Prior to the main stage fieldwork for Wave 1 a pilot was conducted on the full questionnaire to understand the time it took for participants to complete the questionnaire and each individual module within it. The questionnaire was tested over four days with 390 members of Ipsos MORI’s online access panel. The questionnaire took participants on average 26 mins and 48 seconds to complete and it was believed that no alterations were needed to the length of the questionnaire, in order for it to fall within the desired 30 minutes. Pilots were not conducted in Waves 2, 3 and 4 as the expected completion time was estimated from Wave 1 fieldwork.   

Differences in the questionnaire

Due to the modular design of Food and You 2, some questions (core modules) are asked in every wave, whereas other questions are only present in certain waves.  For some questions, the base will vary between Waves 1, 2, 3 and 4.  This is due to changes in the questions available for filtering, and/or their inclusion in the postal questionnaire. Please see the Wave 4 Tables User Guide for details.
The table below notes which modules were present in each wave of the survey, though note the content of each module varied somewhat between waves, as outlined above. 

Table 19: Questionnaire module content of each survey wave

Full list of modules from Waves 1-4	Waves include
About you and your household (core)	1,2,3,4
Food Concerns (core)	1,2,3,4
Food you can trust (core)	1,2,3,4
Household Food Security (core)	1,2,3,4
Eating at home (core questions)	2,4
Eating at home (full module)	1
Food shopping	1,3
Defra questions	1,3
Eating out	2,4
Online food platforms	3
Food Hypersensitivities (core questions)	1,3,4
Food Hypersensitivities (full module)	2
Healthy eating (Northern Ireland only)	3
Emerging issues	4

Differences in fieldwork

Fieldwork dates

The Food and You 2 survey should take place every six months.  However, the length of the initial questionnaire development led to a later start in its first year. The fieldwork dates of each Wave are as follows:

• Wave 1: 29th July 2020 to 6th October 2020 (about 10 weeks)
• Wave 2: 20th November 2020 to 21st January 2021 (about nine weeks)
• Wave 3: 28th April to 25th June 2021 (about eight weeks)
• Wave 4: 18th October 2021 and 10th January 2022 (about 12 weeks)

Sample sizes 

There were just over 21,000 addresses issued in Wave 1, leading to 9,319 returns. Since this was much higher than the target of 6,000 returns, only around 14,000 addresses needed to be issued in Waves 2, 3 and 4.

Vouchers 

As an experiment, each adult who completed the questionnaire in Wave 1 received either a £15 online voucher, £10 online or paper voucher and £5 online or paper voucher. Based on the results, respondents in later waves received only the £10 voucher. The experiment process and results were summarised in an article published on the Social Research Association (SRA) website, Volume 11, Summer 2021. For waves 2-4, all participants received a £10 voucher.

Postal questionnaires

When postal questionnaires were sent out in Waves 1, 2 and 4, the version was assigned to person one and person two in the household on a quasi-random basis. This meant half contained questions from one module and the rest contained questions from another module.  However in Wave 3, one of the modules was only relevant to residents of Northern Ireland.  Therefore, the content of the postal questions varied on a country basis rather than randomly.

Reminders

In Wave 3, the response rate was high enough after Mailing 3 for the final reminder to be sent to just two-thirds of the non-responding sample. In the previous two waves, it was sent to all outstanding non-responding households. In Waves 1, 2 and 4, all non-responding sample received a reminder.

Differences in weighting

Overall, the same weighting approach was taken in Waves 1, 2, 3 and 4. However, in each Wave, some additional weights are needed for those questions that are not asked to all postal respondents. These additional weights will vary between waves depending on which questions are included.

Wave 4 has “Welsh and Welsh-England” weights to easily compare Welsh respondents against a English population calibrated to have similar demographic characteristics. In Waves 1 to 3, the weights for the calibrated English population were called “Welsh England” weights.  The corresponding weights for Welsh respondents were formally part of the individual country level weights.

Differences in data validation and management

In Waves 1 and 2, the tables were created from the underlying data independently of the SPSS dataset.  From Wave 3 onwards, syntax produced the derived variables in SPSS, and this was used to produce the tables in Quantum. As part of this change, the data validation procedures were reviewed and the following improvements made: 

• in all waves, back editing and forwarding editing was applied to inconsistencies in the postal data, with a smaller amount of back editing applied to the Wave 3 and 4 data than in other waves. Back editing meant that if a filtered question was answered but the filter origin question contradicted that answer (blank or different), then the origin question was changed to be the answer for the filter question. Whereas forward edited meant that if a participant answered a question but did not follow the routing to answer the next filtered question they were assigned a code of -99 “Not stated”
• in Waves 1 and 2, if a question was incorrectly answered as a multi-code question when only one answer should have been selected, then a digit from the participant ID was used to randomly select an answer.  In Waves 3 and 4, the responses were set to -99 “Not stated”
• from Wave 3 onwards, an edit was introduced to correct the number of adults when participants from a multiple response household answered that only one adult lived in that household

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