With Cost Sharing: Indirect Costs for Research / (Direct research costs + Cost Sharing Committed) = Indirect Cost Rate
Without Cost Sharing: Indirect Costs for Research / Direct research costs = Indirect Cost Rate
It is apparent the indirect cost rate with cost sharing is lower.
2. Committing cost sharing voluntarily in a proposal usually does not affect the competitiveness of the proposal, unless the sponsor specifically states that non-required cost sharing is encouraged. This is rare.
3. Once the cost sharing is committed, the PI, the department, and the university are all obligated to monitor and track the cost sharing, even if cost sharing/matching is not required by the program. This adds additional administrative effort on all parties, not to mention the administrative effort of counting and adding the total cost sharing to the indirect cost calculation.