Candor on surveys

ADD Health interviewers were asked the following about the study participant: "How candid was the respondent?" Answers ranged from "very candid" (1) to "not candid" (4).  Here are means by race/ethnicity:

Mean evasiveness score (N = 6,477)

Males
White 1.64
Black 1.89*
Mexican 1.82*
Puerto Rican 1.93*
Cuban 1.80 
Amerindian 1.65
Asian 1.66

Females
White 1.55
Black 1.82*
Mexican 1.65
Puerto Rican 1.89* 
Cuban 1.85
Amerindian 1.55
Asian 1.61

*significantly higher than white counterpart


For both sexes, blacks and Puerto Ricans were significantly more evasive than whites. Mexican American males were also less candid than their white counterparts. The largest gap is between whites and Puerto Ricans. It turns out to be one-third of a standard deviation (sd) for males and four-tenths of an sd for females--moderate differences. 

The numbers are consistent with another study I described which found that, compared to whites, blacks and Hispanics score higher on lie scales when participating in surveys. It might simply be due to mistrust of authorities. These results suggest that the true racial gaps in undesirable behaviors like crime might be larger than survey data indicate.