To estimate costs for a project similar to one implemented last year, the project manager met with experts who used a three-point estimating technique. The new sponsor is concerned because the budget is higher than expected. What should the project manager do?

The best approach is to review historical information and lessons learned from the previous, similar project. This provides a factual basis to justify the current budget estimate, especially since the three-point estimate already incorporates uncertainty. This demonstrates due diligence and transparency to the new sponsor. Reviewing the organizational process assessment for contingency reserves is a good practice but doesn't directly address the sponsor's concern about the overall higher budget. Switching to a bottom-up estimate would be time-consuming and might not significantly change the overall estimate if the three-point estimate was already well-executed. Persuading the sponsor without objective justification is unprofessional and unlikely to build trust.