In some studies, self-regulation skills have been shown to predict academic achievement more reliably than I.Q. tests. Observing an individual's ability to self-regulate works as a good predictor of character in all kinds of situations, interviews being one of the more useful applications. Although justifying your subject judgments to your colleagues could be tricky -> "He answered the concurrency questions better th…
Also consider reminding such colleagues that there is a definite, well confirmed negative correlation between conscientiousness and intelligence: http://www.ist-world.org/ProjectDetails.aspx?ProjectId=74c83...
Because assuming people in a certain group have a certain level of skill, it makes sense that people with below average intelligence in that group may be compensating with extra conscientiousness, while people with above average intelligence for that group could have been part of a better group, but their lack of conscientiousness dragged them down.
I.e. being less conscientious doesn't make you more intelligent. Rather, the less conscientious you are, the more likely you are to end up surrounded by people with less intelligence than you (who make up for it with more conscientiousness than you).