The base-year survey of the National Education Longitudinal Study of 1988 (NELS:88) took place in spring 1988. Data on a variety of topics were obtained by questionnaires and achievement tests administered to a national probability sample of 25,000 eighth-graders. This report presents results of an examination of the quality of responses of eighth-grade students to a subset of variables available in the NELS:88 database. The quality of the data was assessed several ways. The correspondence between parent and student responses to similar items on the survey instruments was examined. When data were available, the study examined consistency among responses to related items. Finally, the reliability of several scales created from NELS:88 data was assessed. The indicators of data quality suggest that NELS:88 data display a high degree of accuracy and consistency, comparing favorably with responses from the last longitudinal study of the National Center for Education Statistics, the High School and Beyond Study (HSB). The quality of student responses to items common to both studies was somewhat less for NELS:88 eighth-graders than for HSB high school sophomores and seniors, with quality increasing with age, and, as expected from prior research, with reading ability and socioeconomic status. There are 39 tables of NELS:88 data and 2 illustrative bar graphs. (SLD)