The definition of income for both child support and alimony starts the same. M.G.L. Chapter 208 Section 53b states (with some limitation) that income for determining alimony shall be defined as set forth in the Massachusetts child support guidelines. The child support guidelines define income as "gross income from whatever source regardless of whether that income is recognized by the Internal Revenue Code or reported to the Internal Revenue Service or state Department of Revenue or other taxing authority." The guidelines then go on to list numerous types of income that would be included.
In the child support guidelines, second job and overtime income are addressed immediately after the definition of income and start with the presumption that the income is included. The court can include or exclude all or some of the additional income even if it was earned prior to the initial order, but if the court excludes it they have to consider certain factors "including but not limited to the history of the income, the expectation that the income will continue to be available, the economic needs of the parties and the children, the impact of the overtime on the parenting plan, and whether the extra work is a requirement of the job." Essentially this means the Judge has broad discretion, but starts with the presumption that the income is included unless these factors weigh against that presumption.
Second job or overtime income that starts after the initial order, however, is treated differently:
"If, after a child support order is entered, a Payor or Recipient obtains a secondary job or
begins to work overtime, neither of which was worked prior to the entry of the order, there shall be a presumption that the secondary job or overtime income should not be considered in a future support order."
This encourages people to supplement their income without being punished for it, which makes sense. In addition, this is only a presumption which could be overcome if, for example, the payor was underemployed in the first place and this second job really just brings them up to a more appropriate base income.
Because the standards for determining an amount of alimony vary from those for determining child support, the second job income's affect on the payor's "ability to pay" could result in a different determination than the findings required for including or excluding second job income for child support calculations. However, there is a presumption in both cases that if the income starts after the initial order, then it is not included. This issue was specifically addressed as to an alimony modification by the Appeals Court in the recent Vedensky decision.