Technical appendix Quantitative
The data was collected by an online survey.
The target group for this research study was RPID customers.
The sampling frame used for this study was all customers on the RPID customer database.
The target sample size was between 2,000 and 3,000 responses and the final achieved sample size was 2,147.
Fieldwork was undertaken between 6th August and 6th September 2021.
All eligible customers (those with a valid email address) were selected to take part. Respondents to internet self-completion studies are self-selecting and complete the survey without the assistance of a trained interviewer. This means that Progressive cannot strictly control sampling and, in some cases, this can lead to findings skewed towards the views of those motivated to respond to the survey.
The overall response rate to the survey was 14%. This response rate is good for a survey of this kind.
The sample broadly represents the target population in terms of the spread of responses by local area office.
The final data set was not weighted, due to lack of available population information, and fundamental differences in methodology and customer base with previous iterations of the survey.
The overall sample size of 2,147 provides a dataset with a margin of error of between ±0.39% and ±1.97%. These are calculated at the 95% confidence interval (market research industry standard).
Our data processing department undertakes a number of quality checks on the data to ensure its validity and integrity.
For CAWI Questionnaires these checks include:
- Responses are checked for duplicates where unidentified responses have been permitted.
- All responses are checked for completeness and sense.
Data gathered using self-completion methodologies are validated using the following techniques:
Internet surveys using client lists use a unique invitation link system to ensure that duplicate surveys are not submitted. The sample listing is also de-duplicated prior to the survey launch.
Where some profiling information has been provided on the sample list, this is also checked against responses where possible to validate the data.
A computer edit of the data carried out prior to analysis involves both range and inter-field checks. Any further inconsistencies identified at this stage are investigated by reference back to the raw data on the questionnaire.
Where 'other' type questions are used, the responses to these are checked against the parent question for possible up-coding.
Responses to open-ended questions will normally be spell and sense checked. Where required these responses may be grouped using a code-frame which can be used in analysis.
A SNAP programme set up with the aim of providing the client with useable and comprehensive data. Crossbreaks are discussed with the client in order to ensure that all information needs are met.
All research projects undertaken by Progressive comply fully with the requirements of ISO 20252.