This article describes the work of Oscar Lewis, Paul Willis, and John U. Ogbu, who used the concept of culture to explain the difficulties some children had in schools. Although Lewis, Willis, and Ogbu were well trained as ethnographers and their work influenced educators, critics complained that their explanations did not fit their evidence. The problems derived from what is called a group fallacy because the researchers pointed to a group to explain the behavior of individuals. This does not mean the studies were worthless. They gave examples of people's attitudes in the same way that novelists portray characters. This essay is important to practicing ethnographers because it suggests how the concept of culture can limit the value of their research and how they can correct this possible flaw.