The use of randomized controlled trials (RCTs) to study the impact of specific interventions, has over the last decade become a dominant methodology in development microeconomics

However, some argue that socioeconomic RCTs do not test hypothesis rooted in theory and ignore mechanisms of causality

For example,

"In 2006, approximately 1,300 men and women were tested for HIV. They were then offered financial incentives of random amounts ranging from zero to values worth approximately four month’s wages if they maintained their HIV status for approximately one year..."

"Throughout the year, respondents were asked about their sexual behavior three times, through interviewer-administered sexual diaries. Respondents were then tested for HIV, and financial incentives were awarded based on whether they had maintained their HIV status..."

"After the second round of testing, the incentives program stopped."

Taken from the article 'Conditional Cash Transfers and HIV/AIDSPrevention: Unconditionally Promising?'