Comparability
Comparability is affected by changes in the top code over time and the 2019 questionnaire redesign. In 2018 only, SHOTPNUNO is top coded at "6 shots or more." Beginning in 2019, it is top coded at "3 shots or more." Additionally, the NHIS questionnaire was substantially redesigned in 2019 to introduce a different data collection structure and new content. For more information on changes in terminology, universes, and data collection methods beginning in 2019, please see the user note.
