How do I produce correct estimates for NSDUH: 4- and 2-Year R-DAS data files?

To generate correct estimates for the NSDUH: 4- and 2-Year R-DAS data files, users must use the year pair indicator variable (YRPRIND) in one of the following ways:

1. As a filter to subset the data file for a specific group of years such as:
   - For the 2-Year R-DAS data file use "YRPRIND(1)" for 2002-2003, "YRPRIND(2)" for 2004-2005, "YRPRIND(3)" for 2006-2007, "YRPRIND(4)" for 2008-2009, "YRPRIND(8)" for 2010-2011 or "YRPRIND(10)" for 2012-2013 in the filter field.
   - For the 4-Year R-DAS data file use "YRPRIND(5)" for 2002-2005 or "YRPRIND(6)" for 2006-2009 in the filter field.
2. As a control variable. PLEASE NOTE: This option will produce separate results for each combined group of years (e.g., 2002-2005). The last table with total estimates is invalid and should be ignored.
3. As a row variable in the row field. PLEASE NOTE: Under this option the column total estimates are invalid and should be ignored.
4. As a column in the column field. PLEASE NOTE: Under this option the row total estimates are invalid and should be ignored.

The NSDUH R-DAS data files do not allow for the creation of single-year estimates because of the potential for disclosure of confidential information. The NSDUH R-DAS data files contain revised weights designed to produce estimates that are representative of the average population across combined two-year (2002-2003, 2004-2005, 2006-2007, 2008-2009, 2010-2011, and 2012-2013), four-year (2002-2005 and 2006-2009), eight-year (2002-2009), or ten-year (2002-2011) periods. There are no weights on the 4-year R-DAS that are representative of all eight years; thus all estimates of totals across the period 2002-2009 will be twice as large as they should be. Similarly, there are no weights on the 2-year R-DAS that are representative of all twelve years. To get the correct estimates of totals across the eight year period, the 8-year R-DAS file should be used. Similarly, the 10-year R-DAS file should be used to get the correct estimates of totals across the ten year period.