2015 NATIONAL SURVEY ON DRUG USE AND HEALTH METHODOLOGICAL SUMMARY AND DEFINITIONS DISCLAIMER SAMHSA provides links to other internet sites as a service to its users and is not responsible for the availability or content of these external sites. SAMHSA, its employees, and contractors do not endorse, warrant, or guarantee the products, services, or information described or offered at these other internet sites. Any reference to a commercial product, process, or service is not an endorsement or recommendation by SAMHSA, its employees, or contractors. For documents available from this server, the U.S. Government does not warrant or assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed. Substance Abuse and Mental Health Services Administration Center for Behavioral Health Statistics and Quality Rockville, Maryland September 2016 2015 NATIONAL SURVEY ON DRUG USE AND HEALTH: METHODOLOGICAL SUMMARY AND DEFINITIONS Contract No. HHSS283201300001C RTI Project No. 0213984.004.107.006.004 RTI Project Director: David Hunter SAMHSA Project Officer: Peter Tice For questions about this report, please e-mail [email protected]. Prepared for Substance Abuse and Mental Health Services Administration, Rockville, Maryland Prepared by RTI International, Research Triangle Park, North Carolina September 2016 Recommended Citation: Center for Behavioral Health Statistics and Quality. (2016). 2015 National Survey on Drug Use and Health: Methodological summary and definitions. Rockville, MD: Substance Abuse and Mental Health Services Administration. Table of Contents Section Page List of Figures ................................................................................................................................. v List of Tables ................................................................................................................................ vii Introduction ..................................................................................................................................... 1 A Description of the Survey ................................................................................................... 3 A.1 Sample Design ........................................................................................................ 3 A.2 Data Collection Methodology ................................................................................. 6 A.3 Data Processing ....................................................................................................... 9 A.3.1 Criteria for Identifying Usable Interviews .................................................. 9 A.3.2 Data Coding and Editing ........................................................................... 10 A.3.3 Statistical Imputation ................................................................................ 13 A.3.4 Development of Analysis Weights ........................................................... 17 B Statistical Methods and Measurement .............................................................................. 23 B.1 Target Population .................................................................................................. 23 B.2 Estimation and Statistical Significance ................................................................. 23 B.2.1 Variance Estimation for Totals ................................................................. 24 B.2.2 Suppression Criteria for Unreliable Estimates .......................................... 25 B.2.3 Statistical Significance of Differences ...................................................... 27 B.3 Other Information on Data Accuracy ................................................................... 29 B.3.1 Screening and Interview Response Rate Patterns ..................................... 29 B.3.2 Item Nonresponse and Inconsistent Responses ........................................ 31 B.3.3 Reliability of NSDUH Measures .............................................................. 34 B.3.4 Validity of Self-Reported Substance Use ................................................. 36 B.3.5 Revised Estimates for 2006 to 2010 ......................................................... 37 B.4 Measurement Issues .............................................................................................. 38 B.4.1 Use and Misuse of Prescription Drugs...................................................... 39 B.4.2 Initiation of Substance Use or Misuse ...................................................... 41 B.4.3 Substance Use Disorders........................................................................... 46 B.4.4 Need for Services for Substance Use and Mental Health Issues .............. 49 B.4.5 Definition of County Type ........................................................................ 51 B.4.6 Effects of Questionnaire Changes Prior to 2015 on Mental Health Measures ................................................................................................... 52 B.4.7 Estimation of Serious and Other Levels of Mental Illness ....................... 55 B.4.8 Major Depressive Episode (Depression) .................................................. 65 iii Table of Contents (continued) Section Page C NSDUH Changes in 2015 and Their Effects on Comparability of Estimates .................. 77 C.1 Changes to the Substance Use Questions ............................................................. 77 C.1.1 Tobacco ..................................................................................................... 77 C.1.2 Alcohol ...................................................................................................... 78 C.1.3 Hallucinogens ........................................................................................... 78 C.1.4 Inhalants .................................................................................................... 79 C.1.5 Methamphetamine ..................................................................................... 79 C.1.6 Prescription Psychotherapeutic Drugs ...................................................... 80 C.1.7 Illicit Drugs Overall .................................................................................. 83 C.2 Effects of Changes on Substance Use Disorder and Substance Use Treatment Estimates .............................................................................................. 84 C.2.1 Substance Use Disorders........................................................................... 84 C.2.2 Substance Use Treatment .......................................................................... 84 C.3 New Questions in the 2015 NSDUH Interview .................................................... 85 C.4 Deleted Questions for the 2015 NSDUH Interview ............................................. 85 C.5 Changes in Mode of Administration for the 2015 NSDUH Interview ................. 86 C.6 Miscellaneous Changes for the 2015 NSDUH Interview ..................................... 87 C.6.1 Highest Level of Education ...................................................................... 87 C.6.2 Perceptions of Risk and Availability ........................................................ 87 C.6.3 Driving Under the Influence of Alcohol or Illicit Drugs .......................... 88 C.6.4 Specific Health Conditions ....................................................................... 88 C.7 State and Substate Estimates from the 2015 NSDUH Data .................................. 89 D Key Definitions for the 2015 National Survey on Drug Use and Health ......................... 91 E Other Sources of Data ..................................................................................................... 151 E.1 National Surveys Collecting Substance Use or Mental Health Data in the Civilian, Noninstitutionalized Population ........................................................... 151 E.2 Substance Abuse Treatment Data Sources ......................................................... 167 E.3 Surveys of Populations Not Covered by NSDUH .............................................. 170 F References ....................................................................................................................... 185 G List of Contributors ......................................................................................................... 199 iv List of Figures Figure Page B.1 Required Effective Sample in the 2015 NSDUH as a Function of the Proportion Estimated ........................................................................................................................... 72 E.1 Past Month Alcohol Use among Youths in NSDUH and MTF: 2002-2015 .................. 177 E.2 Past Month Cigarette Use among Youths in NSDUH and MTF: 2002-2015 ................. 178 E.3 Past Month Marijuana Use among Youths in NSDUH and MTF: 2002-2015 ............... 179 E.4 Past Month Marijuana Use among Youths in NSDUH, MTF, and YRBS: 1971- 2015................................................................................................................................. 180 v vi List of Tables Table Page A.1 Target Number of Completed Interviews per Year and Number of State Sampling Regions in the 2013 and 2014-2017 NSDUHs, by State .................................................. 19 A.2 Target Sample Allocation, by Age Group, for the 2013 NSDUH and Each Year in the 2014-2017 NSDUHs ..................................................................................................