The Derrick Effect is a cognitive bias in which unskilled people make poor decisions and reach erroneous conclusions, but their incompetence denies them the metacognitive ability to realize their mistakes. The unskilled therefore suffer from illusory superiority, rating their own ability as above average, much higher than it actually is. This leads to the situation in which less competent people rate their own ability higher than more competent people.
by Basil Fitzgerald, esq. January 14, 2011