From 1965 to 1968, Laud Humphreys conducted an ethnographic study of anonymous male-male sexual encounters in public restrooms, otherwise known as "tearooms" (Humphreys (1970) Tearoom Trade). Due to the study's sensitive subject matter, the study was highly controversial. A number of criticisms were made of the study - complaints that the research was conducted using unethical and dubious methods.
Humphreys observed these encounters at several popular tearooms, offering to serve as a "watch queen" - an individual who keeps watch, alerting the participants when a stranger approaches. Humphreys covertly recorded the license plate numbers of the cars of men he had observed engaging in oral sex with other males. Acquiring the names and addresses through the car registry, he was able to gather a sample of a hundred men. A year later, Humphreys appeared at their homes, acting as a health-service interviewer, asking the men about their marital status, race, and careers.
Laud Humphreys employed qualitative research strategies when conducting his study. He presents the data in the form of a descriptive case study which outlines and analyses the behavioral patterns and socio-economic status of the participants. The majority of the data was gathered through means of covert participant observation. Therefore Humphreys was able to limit participant reactivity, which would cause otherwise unnatural behaviour caused by the knowledge that one is being observed. But a limitation of this method is that field notes are not as accurate and is susceptible to memory bias, that is the recall of the events is susceptible to the personal impressions of the researcher.(Punch 1986) He also employed the use of interviews as a part of his methodology. .
To gain knowledge of socio-economic status as well as marital and family status and career, Humphreys conducted semi-structured interviews with his chosen sample group of men.