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Benchmark Dose Tools

2011 External Review of the MS_Combo Model

In early 2011, the new MS_Combo model was externally reviewed by three experts in dose-response modeling and documented in a MS_Combo Peer Review Report(21 pp, 118 K, 2011-03-03) .

The primary purpose of this review was to ensure that the results of the draft EPA MS_Combo model calculates correct, accurate, and statistically valid estimates of the maximum likelihood and lower bound on a dose corresponding to fixed risk level, for a combination of two or more tumor types.

The peer reviewers were specifically asked to evaluate MS_Combo with respect to clarity of the documentation and model output, and the adequacy of testing methods and test results.

The reviewers generally agreed that the model produced statistically valid results, but made several recommendations regarding enhancements that could facilitate or expand its practical application, and how the documentation and outputs could be improved with respect to clarity.

EPA revised the MS_Combo software and documentation in response to these comments, incorporating most of the suggested revisions.

Some suggested revisions that were considered important but not critical (e.g., reporting the entire estimation-error distribution for each estimated BMD) were postponed for implementation in a future version of MS_Combo. A technical background document for the MS_Combo program contains details necessary to understand the program's assumptions and application.

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