Wave 2 of the National Social Life, Health, and Aging Project: an overview.

(NSHAP) is designed to provide new data to explore how social support and personal relationships are associated with the health and aging in a representative sample of older community-dwelling Americans. NSHAP now has completed two rounds of data collection. There were two important objectives for carrying out the second wave of data collection. First, given the dynamics of health and aging, it was critical that NSHAP allow for longitudinal analyses of health trajectories. Second, because NSHAP is explicitly designed to shed light on the role of social support and personal relationships, Wave 2 (W2) expanded its design to include partners. Underlying these two objectives, the W2 NSHAP data collection effort attempted to balance consistency for longitudinal analysis with allowance for innovative developments. The articles in this special issue highlight W2 data and its potential value to a multidisciplinary research community. This special issue complements and expands on the previous special issue highlighting the Wave 1 (W1) data. The articles were peer-reviewed in accordance with the usual procedures of this journal. We were the guest editors of this special issue and we were happy to see the substantial scientific output of this new survey wave, which has many unique dimensions that distinguish it from other American national surveys, including those supported by the National Institute on Aging (such as this one) and those supported by other sources. Contents of the Issue As noted above, this special issue covers findings from W2 of NSHAP, but several papers also contain data from W1, in order to place the findings in longitudinal context. There are 22 articles that describe, similar to the special issue covering the first wave, the sample design, the measures , methodological elaborations, and basic descriptive findings in the various domains of the survey. In addition, they clearly lay out consistencies between W1 and W2 which enable longitudinal analysis, and they present measures that are new and improved in W2. Recommendations and suggestions about using the data also provide guidance for the research community. The first four articles in the issue provide an overview of W2 study design and methods. Jaszczak and colleagues report that the second wave of data collection for NSHAP resulted in approximately 3,400 in-person interviews, representing an unconditional response rate of 74%, only 2%