The "Theory of Contribution Rate Imputation" estimates developer effort by analyzing historical commit data and typical development rates. Building on the Time-Delta Method, this approach calculates unobserved work periods using metrics like cyclomatic complexity and Levenshtein distance. The Contribution Rate Imputation Method (CRIM) improves upon traditional productivity metrics, offering a more accurate estimation of person-hours spent on software contributions. This method provides valuable insights for project management and resource allocation, helping organizations better understand and optimize developer productivity.