n.a portion of a body records that is selected for permanent retention, in addition to a random sample, to ensure documentation of specific categories of information that might otherwise not be capturedHindus, Hammett, and Hobson 1979, 77Oversample: All cases in the following categories not already chosen for the basic sample will be retained separately and prominently stamped “Oversample.”Ham 1981b, 361This sample also is stratified in that a larger percentage of cases are retained for earlier years. In addition, there is an oversample of all “thick” files and all cases appealed not already included in the basic sample.NARA 1987Information extracted from the 16,750 case files examined in the regular sample in Headquarters, the seven field offices, and two legal attaché offices; and 900 case files examined in the Headquarters multi-section sample, field office oversample (“extras”), and the sample of field office correlates to Headquarters case files examined as part of a comparison sample (“specials”).Norris 1995, 4Oversample categories are those case files that fall into specific categories which are to be preserved apart from or in addition to the random sample. One purpose of oversampling is to ensure that certain categories (e.g., inmates who were executed) are not missed altogether by the random sample due to their modest size.v.to select or collect an oversample of recordsHindus, Hammett, and Hobson 1979, 8We had also hoped to oversample murder and rape cases, but we discovered that this procedure would be too time-consuming.Nelson 1997, 55For example, a researcher looking for letters on open housing legislation would have to oversample the folders on civil rights in order to get a sufficient number of letters for her study.
The point of an oversample is to collect a larger sample of a certain subset of a series to ensure that adequate documentation is available for future research in that area of interest. An oversample, thus, is created when an appraisal concludes that research in that narrow area is likely. A potential drawback of oversampling is that the effort required to collect the sample significantly increases the time needed to collect the overall sample.