BOND is being studied to test what happens when the rules for calculating SSDI benefits of working beneficiaries are changed. As with most new programs, the changes need to be tested to see if they will make a difference. SSA wants to know whether the new BOND program achieves its goals—whether it helps beneficiaries and whether it changes the amount of benefits SSA pays. You may already think that the $1 for $2 benefit offset will make it more likely for SSDI beneficiaries to work, but it is important to be able to provide scientifically reliable evidence of its effects. Creating control groups (one for Stage 1, another for Stage 2) and seeing what beneficiaries in those groups do will help estimate what would have happened to offset group members if they had not been in BOND.