Reassemble
A model is useful when people can use its results and their better decisions move the needle.
From carefully engineered data models and processes and validated quantitative models, we reassemble the new system. We connect data, calculations, and operating processes, replacing components in incremental steps. Each change needs checks that explain whether the result is correct and why it differs from the old one. That makes comparison and verification of the implementation relative to the old easier.
Missing inputs, failed calculations, and changed assumptions are documented and analyzed. We work with the people who will operate and maintain the system, so they can make the next change themselves.