Many researchers assume, under the stress hypothesis, that deployments have a negative effect on military marriages. However, studies on the issue fail to show a correlation between deployment and divorce. “To summarize, service history data over the past ten years do not demonstrate the high rates of marital dissolution predicted by the stress hypothesis” (Karney 23). One way to explain this unexpected result is to look at implementations in a different way. Instead of focusing on the negative aspects, such as leaving one's family behind, they consider the positive aspects associated with military deployments which include increased pay, a sense of purpose and increased opportunities for career advancement. It may also be that, for some military couples, long-term separation from their spouse increases their gratitude for that person and leads them to have a more positive outlook on the situation.