Cohen Lab on Aging, Systems and Statistics

Epidemiology, Statistics, Demography, and Mathematical Modeling

These fields represent methodological tools that form the backbone of our research. We take an integrated approach to quantitative analysis, caring little for the distinctions between these fields. A single article may integrate across all four approaches. Most of our articles contain methodological or quantitative innovations, though relatively few of these are major enough to merit separate publication. We give an extensive description of our approach to quantitative in the Philosophy section.

While publication of quantitative methods in statistics journals has not been our primary focus to date, we have published one article on the (striking!) consequences of categorizing continuous control variables in regression models. (Hint: never, ever do this.) We are also conducting some theoretical work on Mahalanobis distance, the statistical measure we use to measure physiological dysregulation. A fair number of our publications include methodological components introduced to different disciplines, particularly presenting the Mahalanobis distance approach to dysregulation and physiological state.

Chart showing six different malaria indices by district in India

Key methods we use

  • Mahalanobis distance and its variants
  • Principal components analysis
  • Regression (including multi-level models, survival analysis, etc.)
  • Bayesian approaches
  • Null models, empirical distributions, and simulation
  • Functional data analysis
  • Graphical representations of complex data

Selected publications

Watson, H., Cohen, A.A., Isaksson, C. (2015). A theoretical model of the evolution of actuarial senescence under environmental stress. Experimental Gerontology, 71:80-8. http://www.ncbi.nlm.nih.gov/pubmed/26335620

Barnwell-Ménard, JL., Li, Q., Cohen, A.A. (2015). Effects of categorization method, regression type, and variable distribution on the inflation of Type-I error rate when categorizing a confounding variable. Statistics in Medicine, 34(6): 936-49. http://www.ncbi.nlm.nih.gov/pubmed/25504513

Cohen, A.A., Milot, E., Yong, J., Seplaki, C.L., Fulop, T., Bandeen-Roche, K., Fried, L. P. (2013). A Novel Statistical Approach Shows Evidence for Multi-system Physiological Dysregulation During Aging. Mechanisms of Ageing and Development, 134(3-4):110-7. http://www.ncbi.nlm.nih.gov/pubmed/23376244

Cohen, A.A., Tillinghast, J., Canudas-Romo, V. (2010). No Consistent Effects of Prenatal or Neonatal Exposure to Spanish Flu on Late-Life Mortality in 24 Developed Countries. Demographic Research, 22(20): 579-634. http://www.ncbi.nlm.nih.gov/pubmed/21796260 

Cohen, A.A., Dhingra, N., Jotkar, R.M., Rodriguez, P.S., Jha, P. (2010). The Summary Index of Malaria Surveillance (SIMS): A Stable Index of Malaria within India. Population Health Metrics, 8(1). http://www.ncbi.nlm.nih.gov/pubmed/20181218