Researchers conducted a survey on young adults' sexual behavior, and found that many respondents did not answer every question. Specifically, it seems like many people chose to not answer the question, "have you ever had sexual contact with a person of the same sex," most likely because of the stigma of same-sex sexual contact and social desirability concerns (but they did not measure people's social desirability bias). Furthermore, 25 percent of respondents refused to answer the question, "have you have had sexual contact with different people on the same day," but it appears that only those people who reported being in a committed relationship (which was measured) refused to answer this question. In the example, what type(s) of missingness are present?

Question

Quizplus · Accepted Answer

In the example provided, there are indications of two types of missingness in the survey data on young adults' sexual behavior:
b. MAR (Missing at Random): This type of missingness occurs when the propensity for a data point to be missing is related to observed data, but not the missing data itself. In the case of the question, "have you ever had sexual contact with a person of the same sex," the missingness could be due to social desirability concerns or stigma associated with same-sex contact. Since the researchers did not measure social desirability bias, we cannot be certain that the missingness is unrelated to the unobserved data (i.e., the actual behavior). However, the assumption here is that the missingness is related to factors such as fear of judgment, which are observed indirectly through the pattern of non-response, rather than the actual behavior being queried.
c. NMAR (Not Missing at Random): This occurs when the missingness is related to the unobserved data itself. For the question, "have you had sexual contact with different people on the same day," the missingness appears to be directly related to the respondents' behavior, as only those in a committed relationship refused to answer. This suggests that the missingness is directly related to the question's content, which is an indication of NMAR.
Given the information provided, the types of missingness present in the survey data are MAR and NMAR. Therefore, the correct answer is:
e. B and C

Researchers Conducted a Survey on Young Adults' Sexual Behavior, and Found