Similarly, clinical measures, such as blood pressure sphygmomanometry, spirometry, and bone densitometry, have been successfully incorporated into epidemiological and other population-based health research. Investigators seeking to incorporate biophysiological measures must regularly choose between tried and true measures with established validity, reliability, and predictive power and experimental or cutting-edge measures, such as those that may have unknown clinical utility or are newly adapted to home-based collection procedures.

For this reason, in our review of innovative biophysiological methods suitable for population-based research, we include (1) methods with a track record of successful implementation in population-based research, (2) established clinical methods amenable to use in population settings, and (3) emerging and experimental methods with promise for future population research. This review is oriented toward experienced population researchers with interest in health but with limited experience in the collection of objective measures of biological function. We emphasize procedures and rationale for collection of biological measures that can be reasonably implemented in field settings and that can be meaningfully integrated with survey research.

Biological measures collected in the population setting can include direct measures of physical or physiological characteristics (e.g., hip circumference, blood pressure), functional testing (e.g., cognitive function, balance, grip strength), or collection of specimens that require laboratory processing in order to generate analyzable data. Such data may also be generated via experimental design (e.g., neuropsychiatric or olfactory testing). In traditional survey research, such constructs are approximated using self-report or subjective assessment by the study subject or the data collector (or both).

Translation of clinical or other laboratory methods for data and specimen collection to the population setting can occur by replication or adaptation. For example, investigators may choose to replicate the clinical encounter by sending a clinician, nurse, or phlebotomist to the home to conduct a physical examination or venipuncture for blood, or to bring participants into a mobile clinic close to where they live or work. Alternatively, adaptation of clinical or experimental laboratory methods using minimally invasive strategies and nonmedically trained interview personnel may enhance the feasibility of data collection and prove more cost-effective (Rockett, Buck, Lynch, and Perreault, 2004). Furthermore, the thrust for minimal invasiveness in population-based health research