Per IRS Publication 596 Earned Income Credit (EIC), page 8:
Examples of items that aren't earned income include interest and dividends, pensions and annuities, social security and railroad retirement benefits (including disability benefits), alimony and child support, welfare benefits, workers' compensation benefits, unemployment compensation (insurance), nontaxable foster care payments, and veterans' benefits, including VA rehabilitation payments. Do not include any of these items in your earned income.
Earnings while an inmate. Amounts received for work performed while an inmate in a penal institution aren't earned income when figuring the earned income credit. This includes amounts for work performed while in a work release program or while in a halfway house.
Workfare payments. Nontaxable workfare payments aren't earned income for the EIC. These are cash payments certain people receive from a state or local agency that administers public assistance programs funded under the federal Temporary Assistance for Needy Families (TANF) program in return for certain work activities such as (1) work experience activities (including remodeling or repairing public housing) if sufficient private sector employment is not available, or (2) community service program activities.
Community property. If you are married, but qualify to file as head of household under special rules for married taxpayers living apart (see Rule 3), and live in a state that has community property laws, your earned income for the EIC doesn't include any amount earned by your spouse that is treated as belonging to you under those laws. That amount isn't earned income for the EIC, even though you must include it in your gross income on your income tax return. Your earned income includes the entire amount you earned, even if part of it is treated as belonging to your spouse under your state's community property laws.
Nevada, Washington, and California domestic partners. If you are a registered domestic partner in Nevada, Washington, or California, the same rules apply. Your earned income for the EIC doesn't include any amount earned by your partner. Your earned income includes the entire amount you earned. For details, see Publication 555.
Conservation Reserve Program (CRP) payments. If you were receiving social security retirement benefits or social security disability benefits at the time you received any CRP payments, your CRP payments aren't earned income for the EIC.
Nontaxable military pay. Nontaxable pay for members of the Armed Forces isn't considered earned income for the EIC. Examples of nontaxable military pay are combat pay, the Basic Allowance for Housing (BAH), and the Basic Allowance for Subsistence (BAS). See Publication 3 Armed Forces' Tax Guide for more information.
TIP: Combat pay. You can elect to include your nontaxable combat pay in earned income for the EIC.