Fedler hypothesizes that the longevity gap is smaller for married couples than for single people; that marriage only improves the male's longevity and that wealth also helps increase life expectancy. The hypotheses are tested using a dataset on Swiss people who died at age 65 or older in 2001 and 2002, with information on the individuals' age at death and their average lifetime earnings. Fedler uses algorithms, graphs, and other illustrations to show evidence derived from calculations. The study provided evidence suggesting that women live longer than men and that wealth correlates with longevity. The study was valid, but it was conducted using only Swiss deceased and it is difficult to understand life circumstances based only on age at death and income. Another thing I found was that the population was based on deceased people aged 65 or older. I think that to properly measure longevity the study should include participants aged 45 and older. Also limit the description to death from natural causes