An extension of this model has been provided by McCubbin and Patterson (1982), with the recognition that the focus of the original ABCX model is limited to variables present prior to the crisis. In their double ABCX model McCubbin and Patterson (1982) recognize that crisis responding is unlikely to be a static process and posit that variables subsequent to the crisis are important to consider in understanding marital satisfaction and stability. Therefore, they propose that variable A extends beyond the initial stressor to include every day occurrences unrelated to the stressor, in addition to stressors which develop as a result of dealing with the original stressor. Similarly, the level of available resources (B) consists of not only the resources present at the start of the conflict but also those developed through the course of dealing with the stressful event. And finally, the perception of the stressor or event is extended to include the perception of what this crisis situation means to each individual family member post-crisis. This perspective recognizes that the variables associated with marital satisfaction and stability in relation to crises or stressors are ever changing and admits to their importance in the revision of the ABCX model.