The actual causal relationship between race

It seems suspicious that no direct causal connection between race and inc was found. Recall, however, that these are the probabilistic relationships among the responses; they are not necessarily the probabilistic relationships among the actual events. There is a problem with using responses on surveys to represent occurrences in nature because subjects may not respond accurately. Let’s as-sume race is recorded accurately. The actual causal relationship between race, inc, and says_inc may be as shown in Figure 11.11. By inc we now mean whether there really was an incident, and by says_inc we mean the survey

Figure 11.10: The hidden node DAG pattern Tetrad III learned from the racial harassment survey at the .01 significance level.

response. It could be that races, which experienced higher rates of harass-ment, were less likely to report the incident, and the causal influence of race on says_inc through inc was negated by the direct influence of race on inc. This would be a case in which faithfulness is violated similar to the situation involving finasteride discussed in Section 2.6.2. The previous conjecture is sub-stantiated by another study. Stangor et al [2002] found that minority members were more likely to attribute a negative outcome to discrimination when re-sponses were recorded privately, but less likely to report discrimination when they had to express their opinion publicly and there was a member of the non-minority group present. Although the survey of military personnel was intended to be confidential, minority members in the military may have had similar feel-ings about reporting discrimination to the army as the subjects in the study in [Stangor et al, 2002] had about reporting it in the presence of a non-minority individual.