Career Outcome and Lifespan of 6 Classes of Annapolis and West Point graduates: causation and selection/drift effects

Background: Among military officers, as in many comparable civilian settings, a higher final rank usually is associated with a higher life expectancy. Mainly two alternative explanations have to be considered: causation: material and immaterial benefits of a higher rank in active service and thereafter may cause life to last longer. selection/drift: individuals with a robust health may have a greater chance to make it to the top ranks. Data and Methods: We study graduates of classes 1949, 1950, 1951 of the US Naval Academy at Annapolis (n = 2206) and the US Military Academy at West Point (n = 1714), with app. 40%, 49%, 49% equally distributed survivors to Dec 31, 2012. Only graduates with final rank of lieutenant commander/major or higher, in active service over 20 years and more (when they could retire with benefits) were analyzed. Three groups were distinguished: staff officers (lieutenant commander/major, commander/lieutenant colonel) captains/colonels admirals/generals (all levels). Transition from one to the other group is a major advancement in the military hierarchy. Income, however, varies by a factor of 2 at most. Lifestyle and leisure acivities vary little by rank. We apply a fully parametric frailty model: Unobserved effects for PH model can be treated by a positive latent random variable the frailty Z. The frailty concept implies a mixture of individuals in population varying their susceptibility to common risks, We study the covariates military rank, active officer years The most frequently used is the Perks Model (Gompertz Gamma) with Gompertz-specification for Baseline distribution and Gamma-distribution for frailty. The estimator is: ((Formula)), Results ((figure Survival Function)). Admirals/Generals have significant lower mortality than Captains/Colonels, and those than Staff-Officers. These differences, however, diminish with advancing age. Conclusion: Results advance a selection/drift effect: above average health robustness is essential for above average career success in the US military officer corps.