A halfway house that provides housing and support for offenders for the first 3 months after they are released from prison. The halfway house realized that 3 months wasn't always enough time for offenders to get back on their feet so they decided to create an aftercare program that would follow up with the offenders for another three months after they left the halfway house. Program staff have been conducting home visits, doing phone call check-ins, and providing referrals to additional support services when needed. They have documented their interactions and kept data on the participants. The aftercare program has been in place for over a year now and the staff is interested in seeing the effect of the extra support on things like recidivism, drug use, housing stability, and employment. The type of evaluation they should conduct is: Group of answer choices Efficiency Study Impact/Outcome Evaluation Needs Assessment Evaluability Assessment Process Evaluation