Revisiting Classification and Identification

[...]validity refers to how well category membership informs prognosis or treatment. Because the "rules" that define eligibility and the operational procedures used to identify who is and who is not LD vary, the reliability of identification is questionable, thus threatening the meaningfulness of the classification. [...]validity in classification has to do with the kind of information classification provides, the nature of the correlates of the classification. Because LD is only one possible reason for learning problems, any overarching classification of learning problems must allow for other categories.