Select Committee on Social Security Second Report


Details of the size and nature of the sample. How offices and cases were selected

9.1  The Benefit Review pilot of FAMC was designed to test the review methodology and was not intended to produce conclusive statistically valid results. For this reason ASD advised that a sample of 300 would be sufficient to test the methodology and inform a decision on the sample size that would be required for a main study.

Nature of the Sample

9.2  In order to obtain reliable indications of any difficulties in dealing with claims from the self-employed, which make up only about 14 per cent of FAMC claims, it was necessary to over-sample self-employed cases. The sample was therefore stratified to include 200 employed and 100 self-employed cases.

9.3  In order to facilitate the detection of incorrectness it was decided to visit cases as close to the date of adjudication as possible. The standard approach to Benefit Review sampling is to select the sample in one batch, the FIs then having between 6 and 11 weeks to complete their visits. The drawback of using this approach with FAMC is that by the time the FI was nearing the end of the fieldwork his cases would no longer be "fresh" and it was felt this would reduce the chances of finding incorrectness. The sample was therefore selected in three batches, in weeks 0, 4 and 8 of the fieldwork, to ensure that FIs had a steady supply of "fresh" cases to visit.

Selection of Offices

9.4  The liveload of FAMC is approximately 725,000. A selection of 300 cases across the whole country would have produced too wide a geographical spread of customers to make visiting cost-effective so it was decided to draw the sample from 15 locations, allowing 20 cases from each. Statisticians randomly selected 15 offices and FAMS were asked to nominate an investigator from each office.

Selection of Cases

9.5  All paperwork relating to FAMC claims, once actioned, is kept at Filestore at Nelson. No clerical records are stored at the FAMC Unit.

9.6  ASD arranged for FAMC Computer System (FCCS) Support to run three separate scans of the FAMC database, one for each of the three sample batches, at 4 week intervals. ASD provided FCCS with postal districts and postal areas for the 15 sample offices and all claims bearing those post-codes and having a common adjudication date, within a one week window, were listed. Also listed were cases without postcodes.

9.7  The lists were passed to ASD who allocated postcodes to non-postcode cases. This was done in two stages. In the first stage the cases were run through a software package, Quick Address. This allocated the majority of postcodes. In stage 2 the remainder were allocated manually using a gazetteer. Once all cases had postcodes allocated the requisite number of cases was randomly selected for each of the 15 sample offices.

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Prepared 4 February 1999