This is the first report of three that documents an independent evaluation of the Australian Department of Social Services (DSS) Payment by Outcomes Trial 3 (PBO3) over the course of its design and implementation. PBO3 is an exciting and innovative trial that is being led by White Box Enterprises (WBE) as the Australian Government’s contracted service provider. WBE co-developed PBO3 with DSS, social enterprises and impact investors as an innovative mechanism to fund the delivery of long-term employment outcomes for jobseekers experiencing significant barriers to employment. This first report spans PBO3 initiation, design, development and implementation in the first year of service delivery (July 2022 – June 2023). The evaluation consists of: (i) an outcome evaluation focused on how effectively PBO3 has brought about change; and (ii) a process evaluation, which documents design, implementation and operationalisation (inputs, activities and outputs).