NAEP Technical DocumentationMain Quality Control Findings of Interest: Nonresponse Bias Analyses for the 2006 Assessment

School-level nonresponse bias analyses were conducted on private schools at all three grades (4, 8, and 12) and on public schools at grade 12 since the school-level participation rate of each of these groups fell below the 85 percent participation threshold. The analyses involved three components. The first analysis looked for potential bias introduced through the school nonresponse. The second analysis examined the remaining potential for nonresponse bias after accounting for mitigating effects of school substitution. The third analysis examined the remaining potential for nonresponse bias after accounting for mitigating effects of both school substitution and school-level nonresponse weight adjustments.

The analyses suggest that although school nonresponse was quite high for public schools at grade 12 and for private schools at all three grades, there is little evidence of bias.

Student-level nonresponse bias analyses were conducted on grade 12 students in public schools since the student-level participation rates of this group fell below the 85 percent participation threshold. The analyses involved two components. The first analysis looked for potential bias introduced through student nonresponse. The second analysis examined the remaining potential for nonresponse bias after accounting for mitigating effects of the student-level nonresponse weighting adjustment.

Although a number of differences were found to be statistically significant, the large sample sizes resulted in large statistical power, and hence small differences were detected as being statistically significant. Especially after the student nonresponse adjustments were applied, the differences between the respondents and the full samples were very small (one percent or less).

To see the entire report or detailed tables, see NAEP 2006 Nonresponse Bias Analysis Report.

Last updated 07 April 2010 (GF)

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