The "deficit theory" of education posits that students who differ from the norm in a significant way should be considered deficient, and that the educational process must correct these deficiencies.
According to Otto, numerous researchers have studied language differences between economically privileged children and children who live in poverty. These researchers have described differences in terms of dialect, ways in which children use language to describe aspects of their lives and communicative patterns in the families of these children. The researchers noted that children from economically deprived communities did not succeed in school as well as the children from middle- and upper-class environments.
The idea of deficit suggests that there is something wrong with a child who differs from those who naturally succeed in school and places the focus on remediating problems rather than appreciating the strengths all children bring to the classroom upon which a teacher can build to extend knowledge. Lisa Delpit, in an interview with Dana Goldstein, describes watching a researcher in a classroom who was coming to the same deficit theory conclusion middle- and upper-class children compared to economically deprived children. Delpit intervened with the researcher by making a list of the words the economically deprived children knew that the researcher was not aware of, the point being that the way in which research is conducted can limit conclusions. If researchers do not know all about the language children know, how can they determine if a child has a deficit? Delpit suggests that teachers recognize that children who grow up in poverty have a culture that is not well-aligned with the ways schools create knowledge. If teachers make an effort to bridge this gap, rather than focusing on a student-blaming deficit model, then all students can succeed in school.