Document Type


Date of Degree Completion

Fall 2022

Degree Name

Master of Science (MS)


Primate Behavior

Committee Chair

Kara Gabriel

Second Committee Member

Jean Marie Linhart

Third Committee Member

Adrienne Jensen


Capture-recapture (CRC) is a method of population estimation pioneered in biology in the late 19th century. CRC allows the surveyor to approximate the proportion of individuals that evaded the sampling efforts (i.e., captures) based on successful repeated samples from the same population. Hidden populations, such as individuals who experience homelessness, are suspected to elude conventional sampling methods likely because of the social stigma commonly associated with homelessness. By using a local community action agency’s homeless outreach program and cold weather shelter as two distinct sampling sources to capture data, the current study sought to estimate the homeless population in Kittitas County, Washington, as a means of evaluating the utility and ease of CRC methodology. Four months of data collection between the two sampling sources yielded an estimate of 115 homeless individuals in the county. A single day enumeration also called the point-in-time (PIT) count conducted in the same year sampled 61 individuals, supporting the idea that cross-sectional enumeration (i.e., PIT counts) have a history of underestimating the population in question. We propose that CRC enumeration serves to supplement information provided by annual PIT counts that otherwise neglects to capture homelessness as periodic events rather than static states of being.

Available for download on Sunday, December 19, 2027