We were the first to quantify the profound impact that homelessness can have on a person’s life expectancy, proving that homeless men are eight times as likely to die as men in the general population. A large follow-up study, looking at 11 years of national data, found that among those who were homeless or marginally housed across Canada, the probability of survival to age 75 was only 32%. These stark findings were used to advance advocacy and policy arguments across Canada.