1. Section 3: Sweep implementation
From the CLOSER Learning Hub
Module: Study Design

2. Ethical review
Purpose: to ensure sweep is carried out in an ethical manner (secondary analyses do not require additional ethical approvals) Areas of consideration:
Inclusion and exclusion criteria
Participation of vulnerable groups
Contact and consent
Risk of harm
Incentives
Confidentiality and access control
Prior to data collection, the study sweep will typically have to undergo an ethical review, often via a Research Ethics Committee.
The purpose of the review is to ensure that the research is carried out in an ethical manner. It covers a wide range of issues relating to the study and its implementation. In relation to longitudinal studies, a review would typically consider the following areas:
inclusion and exclusion criteria for the study sample
how participants will be contacted, and how their informed consent to participate will be ensured and documented
whether any incentives to encourage participation will be used
consent procedures relating to any requests to link individual study responses to administrative data
how the participation of vulnerable groups will be supported
how the risk of harm to any study participant will be minimised
how data collected as part of the study will be kept confidential and how access to it will be controlled.
Once a sweep has been given ethical approval, individual researchers who use the anonymised data do not need to seek further ethical approvals for each new analysis.

3. Testing Pilot tests to ensure questions are clear to participants
Some studies use actual study participants for pilot tests, others use separate sample
Understanding Society ‘Innovation Panel’
Surveys commonly ‘pre-test’ new questions to make sure that they are clear to study participants. The most common way for longitudinal studies to do this is to carry out ‘pilot tests’. These involve administering all or some of the survey instruments to a group of participants to identify any problems with particular instruments or questions.
Some longitudinal studies use existing study participants to test their questions. This has the advantage of meaning that questions are tested on precisely the group of interest, but risks over-burdening them and increasing the chance that they drop out of the main study. Some studies overcome this by recruiting a sample of people just for the purposes of pre-testing.
Understanding Society has taken a different approach to pre-testing, using what it calls an ‘Innovation Panel’. This is a separate panel of 1,500 households used to test new and innovative ways of collecting data.

4. Fieldwork (data collection)
Notification of participants
Interviewer training
Monitoring of fieldwork: coverage and response rate
Issuing of incentives
The nature of data collection or ‘fieldwork’ will depend on the interview mode being used, and will vary in detail from study to study.
Typically, participants are sent an ‘advance letter’ to let them know about the upcoming sweep and give them details about what happens next.
If the sweep uses interviewers, they need to be briefed and trained. These briefings normally cover the purpose of the research, the administrative procedures the interviewers should follow, and the content of the survey instruments.
Progress is closely monitored during fieldwork, with two key measures being:
Coverage: the number of cases that an interviewer has completed during a specific period
Response rate: the number of completed interviews divided by the number of participants invited to take part
To encourage as high a response rate as possible, some longitudinal studies offer participants a small ‘thank you’ for taking part (usually referred to as an incentive). These typically take the form of vouchers.

5. Data preparation
Editing: checking data quality of the data and, if possible, correcting any errors.
Coding: reducing non-numeric information (e.g. open-ended question) to a numeric form using a coding frame
Anonymisation: replacing names with serial numbers and removing any responses that could disclose someone’s identity
Once the fieldwork is underway, data preparation can begin. If paper questionnaires have been used, the results will have to be scanned or manually keyed so that they are in digital form.
Two key features of data preparation are editing and coding:
Editing involves checking the quality of the data and, if possible, correcting any errors. Editing is greatly reduced through computer-assisted interviewing, as the scope for errors can be limited by the original computer programme.
Coding is necessary when information has been collected from participants in a non-numeric form, for example in open-ended questions. This information needs to be reduced to a numeric form before it can be analysed. Coding often involves a researcher examining the range of responses to the question and developing a ‘code frame’ that lists the possible answers or themes within the answers, and assigns them each a code.
Before the dataset is finalised, it will be reviewed to ensure that it has been adequately anonymised. This includes, for example, removing any verbatim responses that could disclose someone’s identity (for example, if they mention having a very unusual job). Serial numbers are used instead of names, and in longitudinal studies the serial numbers are used to link datasets from different sweeps together.

6. Data access
ESRC-funded studies: data available via the UK Data Service (
MRC-funded studies: apply directly to the study team
More details: resources/access-data
The procedures governing access to study data vary from study to study.
Data from studies funded by the Economic and Social Research Council are deposited at the UK Data Service, where they are made available to bona fide researchers under a licence agreement.
Studies funded by the Medical Research Council require researchers to apply directly to the study team to access the data. The application procedures is different for every study.