Family power is important to those who want to understand how families function as a unit to make decisions about how to manage money, about where to live, about occupational and educational choices, about parenting practices, about where to go on a vacation, and so on. Family scientists define power in terms of who is able to influence others to get their way in the family, and who is able to block others from getting their way. In most cases, family power is a property of the family system, not of a single individual, because it is almost impossible for one individual to have their way all of the time. Although the rules that govern power in a particular family may evolve as children are born, grow up, and move out, as the marital relationship changes or dissolves, or as the circumstances of the family changes, power is deemed to be fairly predictable within these stages. This predictability can be a comfort to those family members who are happy with the power arrangements or a matter of disdain, perhaps even a matter of personal health and safety, for those who find themselves dominated by others.
Ronald Cromwell and David Olson (1975) classified family power into three areas: power bases, power processes, and power outcomes.