Science and Engineering Indicators (Indicators) contains data compiled from a variety of sources. This appendix explains the methodological and statistical criteria used to assess possible data sources for inclusion in Indicators and to develop statements about the data. It also provides basic information about how statistical procedures and reasoning are applied.

This appendix has four main sections, a glossary, and information on viewing the data sources for this report. The first section describes the considerations that are part of the selection process for information to be included in Indicators. The second section discusses the different sources of information (e.g., sample surveys, censuses, and administrative records) used in the report and provides details about each type. The third section discusses factors that can affect accuracy at all stages of the survey process. The fourth section discusses the statistical testing used to determine whether differences between sample survey-based estimates are statistically significant—that is, greater than could be expected by chance. The glossary covers statistical terms commonly used or referred to in the text. The appendix concludes by providing information on how to access the report’s data sources, which can be viewed by chapter and by data provider.