 Dugdale became a member of the executive committee of the Prison Association of New York in 1868 and in 1874 was delegated to inspect thirteen county jails in upstate New York.Noticing that many of the inmates were related by blood or marriage, he self-funded a study of a family living in and around Ulster County, New York, whom he named "Jukes".Using local records and interviews he created detailed family trees and described the lives and histories of individual offenders, and then developed conclusions about what he believed were the causes of crime and dissipation.