The Stanford Center Longevity sponsored an interdisciplinary consensus conference of national experts in January, 2014, to launch THE SIGHTLINES PROJECT. The group identified an extensive list of empirically-validated predictors of longevity and wellbeing, and categorized them by domain. A project team headed by SCL division heads sought out sources of data on each of these topics in nationally representative, high-quality, large-scale data sets which consistently measured the concepts and metrics of interest over the past two decades. Where desirable thresholds were available, analysis compared the percentage of Americans who met the threshold for the most recent year available (typically 2014 or 2013) as well as prior years as long ago as 1995. The key was to compare not just overall trends, but how each age cohort (e.g. 25- to 34-year-olds) scored relative to the same cohort in prior years. Especially where differences emerged, we were able to better understand those differences by looking at subgroups in each time period. For example, to understand changes in home ownership between now and then, we looked at home ownership within each age group who were married versus those that were not.
We honed in on differences between groups OR over time of five percent or more. Given the size of the data sets, and therefore the size of groups being compared, this cut-off reduced the likelihood that differences would be attributable to sampling error. Initial results and successive iterations were shared and reviewed with experts. Alignment with prior research was investigated.
Obviously, the three selected domains and the specific behaviors and conditions discussed in this report do not cover all possible contributors to long life and wellbeing. Specifically, we focused on behaviors that are:
supported by compelling scientific evidence of improved longevity and wellbeing;
tracked by existing, authoritative, nationally representative studies of Americans across the age spectrum at multiple points in time over the last 20 years;
malleable – that is, that individuals and/or society are able to affect.
We were limited by existing measures and samples. Despite the importance of technology-based social engagement, for example, many did not exist 15 to 20 years ago and are not represented in large scale studies. Others were not covered in this report because they have mixed or unknown impact on key areas (e.g. social engagement, financial security) and ultimately wellbeing and longevity. Annual check-ups, for example, are not included in this report because research has failed to support reliable positive impacts on long-term wellbeing.
Regrettably, considerations of race/ethnicity, gender, education and age interactions were often limited by small sample sizes. Further drill downs into specific sub populations will be pursued as we move forward.
Data were drawn from nationally representative, high-quality, large-scale, multi-year studies.