These findings have important implications for substance use and other psychiatric surveillance and epidemiology where meaningful cross-temporal comparisons are desired. Clearly, improvements in sampling, measurement, and nosology occur along with scientific progress and slavishly adhering to past methods to insure strict comparability can result in anachronistic measures and constructs. However, it is always desirable to embed methods and measures that will allow strict comparison on a restricted set of criteria and/or set of participants to be able to gauge the extent that underlying phenomena of interest are showing valid change. It is notable that the seemingly minor differences in NLAES and NESARC could lead to such large discrepancies on important outcomes such as estimates of lifetime AUD even within the same DSM-IV diagnostic framework. For instance, Chung, Martin, Armstrong, & Labouvie (2002) compared various adolescent AUD studies and found substantial differences in dependence prevalence across them. These discrepancies appeared to be primarily attributable to how some symptoms (e.g., tolerance) were operationalized (see also Caetano & Babor, 2006, for a related issue). This problem becomes even more acute when comparing studies
