Mirror sample is a term used when the researcher suspect that the respondents may not tell the truth about their behaviour, he can use a mirror sample. Instead of asking about "you", ask e

ach respondent to think of a close friend of the same sex and age group, and ask them to answer for that friend - without naming the friend. The theory is that, because they don't know all the details about their friends, they'll really describe their own behaviour. Mirror samples have been used in surveys on sexual behavior and on studies about AIDS. This technique is similar to third person technique.