Living Costs and Food Survey technical report: financial year ending March 2022

This report provides an update on the sampling, fieldwork and data processing for the Living Costs and Food Survey (LCF) for the financial year ending (FYE) 2022 (April 2021 to March 2022). The survey is undertaken by Social Survey Collection, which is part of the Surveys Directorate within the Office for National Statistics (ONS).

This report contains response information, questionnaire changes and new or changed methodology for FYE 2022. It does not describe methodology that has changed prior to FYE 2022. For changes prior to FYE 2022, users should refer to our Living Costs and Food Survey technical report: financial year ending March 2021. For a more in-depth explanation of LCF processes and methodology, users should refer to the Living Costs and Food Survey QMI. 

The purpose of this report is to update the FYE 2021 technical report and accompanies our Family spending in the UK: March 2021 to April 2022 bulletin.

Alongside this report, we are publishing updated Living Costs and Food Survey: technical report data tables that provide information on response, characteristics of the sample, confidence intervals and interview metrics.

As shown in Table 4 of the accompanying dataset, the overall response rate for the Living Costs and Food Survey (LCF) in Great Britain was 27% in the financial year ending (FYE) 2022. This is a 3% increase in comparison with FYE 2021.

Of the eligible sample for FYE 2022, it was not possible to contact 42% of addresses, a further 32% refused to take part and 5% had another reason for non-response. Of the 5,306 responding households in Great Britain, 5,227 cooperated fully, meaning they completed both interview and diary sections of the survey.

In FYE 2022, partial responses accounted for 1% of all co-operating households. Of these 79 partials, 76 occurred because one or more adults in the household refused to keep the diary but were happy to take part in the interview (Table 6). 

Interviewers record the main reason why people refuse before or during an interview from a list of pre-coded answers. In FYE 2022, the two most commonly cited reasons for refusing to take part in the survey were (Table 10): 

• cannot be bothered (31%), which was the top reason cited, as in the previous year
• refusal to headquarters after interviewer's visit (10%), which is a level similar to the previous year

Preparations for the April 2021 questionnaire changes began in September 2020. This allowed us to plan the changes and liaise with, and seek, stakeholder approval.

Changes for April 2021

Because of the UK still being under certain restrictions due to coronavirus (COVID-19), most of the changes for the April 2021 questionnaire were related to updating the time period within the questions related to the coronavirus pandemic.

Blocks or questions removed

Following interviewer feedback, a block of questions asking respondents to compare their spending during and before coronavirus was removed to reduce respondent burden and shorten the length of the questionnaire.

Addition of questions

A set of questions were introduced to measure the effectiveness of the Knock to Nudge (KtN) trial that was introduced in October 2020. KtN involved interviewers visiting households to "nudge" those selected to participate in ONS surveys. Thus, offering survey participants an opportunity to schedule a telephone appointment with the interviewer at the doorstep, and for the interviewer to build a rapport with the respondent. For non-contacts, a call today card, indicating that the interviewer had visited the address, was posted through the door. These questions were included for Great Britain only, that is, not Northern Ireland.

The set of questions related to Health were reintroduced into the questionnaire at the request of users, following their removal in April 2020.

Other changes

An updated version of the UK Standard Occupation Classification (SOC) coding frame, SOC 2020, was implemented in July 2022. It was updated because of missing information in the coding frame version introduced in April 2021. This caused only marginal net change at the SOC Major Group level so the impact of the error on LCF outputs was minimal.

Steps were also taken at the data editing stage to check the data against the new SOC coding frame. For further information, users can refer to The impact of miscoding of occupational data in Office for National Statistics social surveys, UK.

The question wording of the coronavirus expenditure questions was updated following interviewer feedback, to improve the flow of the questionnaire.

Because of a change in the TV licensing laws, the routing to the question asking if anyone in the household has paid for a TV licence for the property in the last 12 months was amended to ask all households regardless of the ages of the respondents.

Previously all over-75s used to get a free TV licence, but the rules changed in August 2020, and free licences are now only available to over-75s who receive the pension credit benefit.

Changes made to the questionnaire in response to the pandemic

The actions implemented to continue the survey while coronavirus restrictions were in place were carried forward into 2021 -- please see Living Costs and Food Survey technical report: financial year ending March 2021 for more detail.

For the financial year ending (FYE) 2022, interviews continued to be held over the telephone to ensure data collection activities were carried out in line with the coronavirus restrictions over this period. The introduction of new questions and reintroduction of previously asked questions were kept to a minimum to make sure that the survey length was not increased significantly. The question prompts remained to continue to inform interviewers as to how the questions should be asked.

Design factor

The design factor, or deft, is the ratio of the standard error of an estimate calculated considering the complex design relative to the standard error that would have resulted had the survey design been a simple random sample of the same size. Design factors are estimated for some of the main variables on LCF. These are published in the technical report tables.

The size of the deft varies between survey variables according to the degree to which a characteristic is clustered within primary sampling units (PSUs), or is distributed between strata, and the impact of the weighting. For a single variable, the size of the deft also varies according to the size of the subgroup on which the estimate is based and on the distribution of the subgroup between PSUs and strata.

Deft below 1.0 show that the standard errors associated with the complex design are lower than those associated with the simple random design probably because of the benefits of stratification. Deft greater than 1.0 show the survey has produced less precise estimates than would be obtained from a comparable simple random sample because of the effects of clustering and weighting.