Economic Rates of Return (ERR)
Tanzania’s Economic Rate of Return (ERR) Project Spreadsheets
Each compact project has a downloadable spreadsheet file containing:
- A description of the project, including its economic rationale;
- The expected project impacts, including detailed cost and benefit estimates;
- A tool allowing users to modify key assumptions and study the effects of those modifications on the project’s returns.
Some familiarity with cost-benefit analysis will be essential to use these spreadsheets.
Spreadsheet Data
What the spreadsheet data represent:
- An overall impact estimate. The spreadsheets provide MCC’s best pre-investment estimate of the likely economic impact of the project and form the basis for monitoring and evaluation efforts.
- Estimated benefits. The spreadsheets estimate the expected increases in either incomes or value added of individuals, households, firms or sectors of economic activity.
- A counterfactual scenario. Potential benefits are compared against what is likely to happen without the project (e.g., a growing economy would be expected to continue growing, even without the project).
- A snapshot in time. The spreadsheets reflect the best data available to MCC at the time the project was approved for investment.
What the spreadsheet data do not represent:
- The sole reason for an investment decision. Although ERRs are an integral part of MCC’s decision-making process, other factors are taken into account when MCC decides whether or not to undertake a project.
- A detailed beneficiary analysis. The ERR spreadsheets portray the overall economic impact of a project rather than apportioning the income gains along various demographic dimensions.
- Up-to-the-minute information for projects in implementation. Many of the parameters that are used in these pre-investment estimates change over time, so ERRs may not reflect the actual implementation experience. When project designs or model parameters change significantly, MCC may revise these models; updated information will be posted here as it becomes available.

