The survey results presented in the default charts and tables on this site represent all valid surveys received in each survey year. In most cases, these results represent the combined results for all 6th-, 8th-, 10th-, and 12th-grade students. In different survey years, some school districts and schools refused to participate or chose to not survey some of their grade levels. In those cases, the site presents the results in the default charts, but they may not represent the entire county or all four of the targeted grade levels. The same limitations apply to the results by gender.

The survey research team designed the PNA to estimate grade-level survey results. Consequently, the website filters grade-level results to include only valid and representative results for the different geographies. For instance, the website does not present grade-level results for a county when a large school district in the county did not participate. The research team also excluded grade level results when response rates were too low. Additionally, to protect student anonymity and to ensure data validity, the website only presents grade-level results when 30 or more students participated in the survey. Aggregated results for 6th and 8th grades, or 10th and 12th grades combined may be available if individual grade level results are not.

When there are limitations, the data results pages describe them in the chart's footnotes.

Additional information about sample size, weighted/unweighted data, etc. can be found by downloading the Excel file in the sidebar.