EWCB 2022: Methodology

The survey was first completed in November 2017 to inform the EWCB programme objectives. In May 2020, the FSA in NI made the decision to convert from a biannual survey to an annual survey.

Survey methodology 

The first five EWCB surveys conducted between November 2017 and November 2019 were completed using online panels. In the 2020 survey, interviewing was initiated via Computer Assisted Telephone Interviewing (CATI) (318 interviews). To improve the response rate during the 2020 survey (wave 6), Computer Assisted Personal Interviewing (CAPI) was introduced (283 interviews). CAPI is referred to as ‘face-to-face interviewing’, however due to the COVID-19 pandemic, surveys were conducted via doorstep interviewing instead of directly face-to-face in-home. In 2021 (wave 7), all surveys were completed using the CAPI doorstep method that was introduced in the previous year. In 2022 (wave 8), data was collected solely using the traditional face-to-face in-home CAPI interviewing method. As the 2020, 2021 and 2022 survey used similar interviewing methodology, the results from these years are considered comparable. Significant differences in the 2022 findings compared to the 2021 and 2020 survey have been included throughout this report.  

Survey questionnaire 

The FSA in NI EWCB survey monitors the progress of the EWCB programme through collecting robust consumer insight data on the following: 

• knowledge of daily recommended calorie intake. 
• are consumers in favour of manufacturers reducing sugar, and/or saturated fat, and/or salt content of foods, and portion sizes of food high in these nutrients? 
• ease of selecting healthier choices in food for consumption inside and outside the home. 
• do consumers look at front of pack traffic light labels? 
• do consumers look for calories, sugar, saturated fat, salt, and portion size on packaged food labels?  
• would they like to see high fat, sugar, or salt snacks having a maximum number of calories? 
• does this influence consumer’s choice? If so, how? 
• what do consumers look for/would they like to see, and have they used calories on menus when eating outside the home? 

A copy of the survey questionnaire can be found in the Appendices. 

Sampling and sample size 

A total of 611 interviews were completed with food shoppers in NI in the 2022 report. Interviewing took place from 17th September to 19th November 2022.   

To ensure representation of the population of NI, quota sampling was adopted. Quotas were based on 2011 Census data (Census Office for Northern Ireland, 2011) on key demographic variables in the sample, ensuring representation across gender, age, socio-economic group and region of NI. Quotas and the definition of each socio-economic group can be found in the Appendices. 

In 2021, a total of 603 interviews were completed with food shoppers in NI between the 18th August to 9th October 2021 using the CAPI method. In 2020, a total of 601 interviews were completed between the 5th June to 23rd August 2020 (318 interviews were completed using CATI and 283 using CAPI).   

Data analysis 

The data file was cleaned, weighted, validated, and anonymised. In 2022, corrective weighting on demographic variables was required given some deviation from quotas. Rim weighting was used to weight the data to the target sample for each demographic grouping.  

Significance testing was carried out on data to identify any differences in the views, attitudes, and behaviours of key sub-groups. Statistical significance testing establishes whether the variation between groups could have happened by chance or whether it is likely to reflect some 'real' differences in the population. Only statistically significant differences are reported between each year of the survey from 2020 to 2022. 

A range of demographic information was collected during the survey, such as age, gender, socio-economic group, and the presence of children in the household to enable sub-group analysis. Demographic differences have been reported where statistically significant differences occur at the 5% level. This means that if a statistical difference was found, there is less than a 5% chance that this difference has occurred by chance. Solid green arrows denote a significantly higher difference against the previous year, solid red arrows denote a significantly lower difference. Significant differences between 2022 and 2020 are denoted by a striped green arrow for significantly higher and a striped red arrow for significantly lower. Full data tables are available on request.  

Research considerations 

Results should be interpreted with care. Surveys are subject to errors in participants’ interpretation of survey questions and response options. The data reported within this report relies on participants’ self-reported behaviours. Errors could occur due to imperfect recollection, or participants’ tendency to overreport behaviours which are perceived as being desirable and underreport undesirable behaviours.