The silent majority: The typical Canadian sex worker may not be who we think

Background Most sex worker population studies measure population at discrete points in time and very few studies have been done in industrialized democracies. The purpose of this study is to consider how time affects the population dynamics of contact sex workers in Canada using publicly available internet advertising data collected over multiple years. Methods 3.6 million web pages were collected from advertising sites used by contact sex workers between November, 2014 and December, 2016 inclusive. Contacts were extracted from ads and used to identify advertisers. First names were used to estimate the number of workers represented by an advertiser. Counts of advertisers and names were adjusted for missing data and overcounting. Two approaches for correcting overcounts are compared. Population estimates were generated weekly, monthly and for the two year period. The length of time advertisers were active was also estimated. Estimates are also compared with related research. Results Canadian sex workers typically advertised individually or in small collectives (median name count 1, IQR 1-2, average 1.8, SD 4.4). Advertisers were active for a mean of 73.3 days (SD 151.8, median 14, IQR 1-58). Advertisers were at least 83.5% female. Respectively the scaled weekly, monthly, and biannual estimates for female sex workers represented 0.2%, 0.3% and 2% of the 2016 Canadian female 20-49 population. White advertisers were the most predominant ethnic group (53%). Conclusions Sex work in Canada is a more pervasive phenomenon than indicated by spot estimates and the length of the data collection period is an important variable. Non-random samples used in qualitative research in Canada likely do not reflect the larger sex worker population represented in advertising. The overall brevity of advertising activity suggests that workers typically exercise agency, reflecting the findings of other Canadian research.