  This paper presents a method for estimating the overall size of a hidden
population using results from a respondent driven sampling (RDS) survey. We use
data from the Latino MSM Community Involvement survey (LMSM-CI), an RDS dataset
that contains information collected regarding the Latino MSM communities in
Chicago and San Francisco. A novel model is developed in which data collected
in the LMSM-CI survey serves as a bridge for use of data from other sources. In
particular, American Community Survey Same-Sex Householder data along with
UCLA's Williams Institute data on LGBT population by county are combined with
current living situation data taken from the LMSM-CI dataset. Results obtained
from these sources are used as the prior distribution for Successive-Sampling
Population Size Estimation (SS-PSE) - a method used to create a probability
distribution over population sizes. The strength of our model is that it does
not rely on estimates of community size taken during an RDS survey, which are
prone to inaccuracies and not useful in other contexts. It allows unambiguous,
useful data (such as living situation), to be used to estimate population
sizes.
