The most direct and effective measure of a contractor's cost-based performance for trash collection is the cost per unit of output. In this scenario, the primary output is the amount of trash collected, typically measured in tons. "Cost per ton of trash collected" is a classic efficiency measure that directly links the financial inputs (costs) to the primary service output. This metric allows the local government to assess how efficiently the contractor is using resources to accomplish its core task, providing a clear basis for performance evaluation and comparison over time.

A. per mile travelled. This measures the cost of operating vehicles, an input/process metric, not the cost of achieving the primary objective (collecting trash).

C. comparison with closest comparable jurisdiction. This is a benchmarking method used for external comparison, not a direct, intrinsic measure of the specific contractor's operational performance.

D. per employee. This is a labor productivity metric that ignores other significant operational costs such as fuel, vehicle maintenance, and disposal fees.

1. U.S. Government Accountability Office (GAO). (2011). Performance Measurement and Evaluation: Definitions and Relationships (GAO-11-646SP). On page 6, an "efficiency measure" is defined as "The ratio of the level of resources used (inputs) in an activity to the level of goods and services produced (outputs)." Cost (input) per ton of trash collected (output) is a direct application of this principle.

2. Ammons, D. N. (2001). Municipal Benchmarks: Assessing Local Performance and Establishing Community Standards (2nd ed.). M.E. Sharpe. Chapter 10, "Solid Waste Collection and Disposal," identifies "Collection cost per ton" as a key efficiency and cost-effectiveness measure for evaluating municipal solid waste services (p. 168).

3. Poister, T. H., Aristigueta, M. P., & Hall, J. L. (2015). Managing and Measuring Performance in Public and Nonprofit Organizations: An Integrated Approach (3rd ed.). Jossey-Bass. The text discusses efficiency measures as relating the costs of resources to outputs. In the context of solid waste, this is exemplified by calculating the cost per ton of refuse collected (Chapter 4, "Developing Meaningful Performance Measures").