Iranian Journal of

  Sensitive questions about people’s behaviors are often discussed in studies in the fields of human, social, and medical sciences. Obtaining valid answers to these kinds of questions is one of the main challenges in the mentioned studies. The most important risk factors for the validity of these studies are response bias and non-response bias, which occur because of concerns about divulging personal information. Therefore, researchers are to find solutions other than direct questioning to increase the validity of obtained results through reducing these biases.

  In this review article, we discuss the Warner Model, the Unrelated Question Model, the Forced Response Model, the Moors Model, and the Mangat Model that are subsets of the Randomized Response Technique, and also the Triangular Model and Crosswise Model that are subsets of the Non-Randomized Response Technique. The models are all used in answering sensitive binomial questions.