The investigation of family interaction presents several challenges. F
amilies present methodologic problems because they are an unusual unit
for analysis. Most researchers examine the individual as the central
unit of analysis, but studies of the family must focus on larger units
, such as the dyad, the triad, and the entire family system. Although
important efforts have been made to classify these relationships and t
he individual tendencies in them, much more theoretic and empiric work
remains to be done.