The Secretary, directly or through grants, contracts, or interagency agreements, shall conduct research on the benefits, effects, and costs of operating different State programs funded under this part, including time limits relating to eligibility for assistance. The research shall include studies on the effects of different programs and the operation of such programs on welfare dependency, illegitimacy, teen pregnancy, employment rates, child well-being, and any other area the Secretary deems appropriate. The Secretary shall also conduct research on the costs and benefits of State activities under section
607 of this title.