There are two types of dependents, "Qualifying Children"(QC) and standard ("" in IRS parlance even though they don't have to actually be related). There is no income limit for a QC but there is an age limit, a relationship test and residence test. Only a QC qualifies a taxpayer for the Earned Income Credit.
The support test for a Qualifying Relative is that the taxpayer provided more than half the dependent's support.
The support test for a Qualifying Child is only that the child didn't provide more than half his own support. That may sound like a subtle difference, but for some families it's vital
