¹Among all the NELS 1992 12th-graders who had enrolled in postsecondary education in 1992-2000, about 8 percent did not have complete transcript records and 9 percent did not have information on their parents’ education. (return to text)

²The NELS samples are not simple random samples, and therefore, simple random sample techniques for estimating sampling error cannot be applied to these data. The DAS takes into account the complexity of the sampling procedures and calculates standard errors appropriate for such samples. The method for computing sampling errors used by the DAS involves approximating the estimator by balanced repeated replication of the sampled population. The procedure is typically referred to as the balanced repeated replication method. The website address to view standard errors for all report estimates is http://nces.ed.gov/das/library/reports.asp. (return to text)

³A Type I error occurs when one concludes that a difference observed in a sample reflects a true difference in the population from which the sample was drawn, when no such difference is present. (return to text)

⁴ U.S. Department of Education, National Center for Education Statistics, A Note from the Chief Statistician, no. 2, 1993. (return to text)

⁵Ibid. (return to text)

⁶ More information about ANOVA and significance testing using the F statistic can be found in any standard textbook on statistical methods in the social and behavioral sciences. (return to text)

⁷ For more information about least squares regression, see Lewis-Beck (1980) and Berry and Feldman (1987). (return to text)

⁸ For more information about commonality analysis, see Pedhazur (1997). (return to text)

⁹ See Aldrich and Nelson (1984). Analysts who wish to estimate other types of models can apply for a restricted data license from NCES. (return to text)

¹⁰ See for example, Goodman (1976) and Knoke (1975). (return to text)

¹¹ The adjustment procedure and its limitations are described in Skinner, Holt, and Smith (1989). (return to text)