One of the early fundamental models of planned change was provided by Kurt Lewin. He conceived of change as modification of those forces keeping a system’s behavior stable. Specifically, a particular set of behaviors at any moment in time is the result of two groups of forces: those striving to maintain the status quo and those pushing for change. When both sets of forces are about equal, current behaviors are maintained in what Lewin termed a state of “quasi – stationary equilibrium. “ To change that state, one can increase those forces pushing for change, decrease those forces maintaining the current state, or apply some combination of both. For example, the level of performance of a work group might be stable because group norms maintaining that level are equivalent to the supervisor’s pressures for change to higher levels. This level can be increased either by changing the group norms to support higher levels of performance or by increasing supervisor pressures to produce at higher levels. Lewin suggested that modifying those forces maintaining the status quo produces less tension and resistance than increasing forces for change and consequently is a more effective change strategy.