Data Alert! An accurate comparison of estimates between the redesigned NSCH (2016 and forward) and prior surveys cannot be made due to substantive changes in sampling frame and data collection modes, in addition to questionnaire content and wording in many cases. Any observed differences in estimates before and after the redesign, or lack thereof, may be attributable to design changes and it is not possible to identify true changes over time. Therefore, combining or comparing data from before and after the redesign is not recommended.