We selected 2002 as the start of the observation period as prior surveys had significant methodological differences. We selected 2014 as the end of the observation period as opioid use questions were redesigned in the 2015 NSUDH precluding comparisons after 2014. The selection from 2002–2014 thus allowed us to capture the broadest time period possible that would include the years during which the prescription opioid supply was changing for which comparable year-to-year data were available. Participants aged 18 and older were included in analyses. Survey response rates from 2002 to 2014 ranged from 58.3% to 71.3%.
