The project has shown a declining schedule performance index (SPI) over the past four reviews. No corrective actions are underway, and the team seems unconcerned. What should the project manager do first to address the SPI trend?

The project manager's first step should be to engage the project team to develop a plan for incremental benefit delivery. A declining SPI indicates schedule issues, and involving the team fosters ownership and leverages their expertise to identify solutions. Focusing on incremental benefits allows for early value delivery and provides opportunities to adjust the plan based on progress, which is a core agile principle often applied in such situations. Notifying stakeholders about scope reduction is premature; the team should first explore solutions. Contacting the sponsor for more resources is also premature without a clear understanding of the root cause and potential internal solutions. Rebaselining the project without understanding the underlying issues and involving the team is a reactive measure that doesn't address the core problem and can mask performance issues.