Alimony and child support are generally based largely on what each of the divorcing spouses can reasonably earn. That means that if a person is deliberating working at a job that pays less than what he or she could earn, the courts will sometimes calculate the support amount based on a higher figure.

For example, if a school teacher who earns $50,000 a year decides teaching is just too stressful and goes to work instead as an Assistant Manager at CVS earning $33,500, a judge might decide to calculate the support amount that spouse should pay based on the teacher’s level of income. 

When facts suggest underemployment has occurred, the person who has changed jobs will usually be expected to present evidence on why personal factors such as the stress (as suggested above) made the change necessary. Sometimes a psychologist is called as an expert witness to back-up the need for a change. The person opposing a reduction in support will often succeed if he or she can show that the lifestyles of those who are being supported will be severely affected by the loss of substantial support payments.

Attorney Irwin M. Pollack has often consulted or engaged employment experts to testify to whether a party is working to their fullest potential or, alternatively, underemployed.  He summarizes the underemployment tactic as a common trick that's often played during the divorce process.