Early Phase Cost Models for Agile Software Processes in the US DoD

Background: Software effort estimates are necessary and critical at an early phase for decision makers to establish initial budgets, and in a government context to select the most competitive bidder for a contract. The challenge is that estimated software requirements is the only size information available at this stage, compounded with the newly increasing adoption of agile processes in the US DoD. Aims: The objectives are to improve cost estimation by investigating available sizing measures, and providing practical effort estimation models for agile software development projects during the contract bidding phase or earlier. Method: The analysis explores the effects of independent variables for product size, peak staff, and domain on effort. The empirical data for model calibration is from 20 industrial projects completed recently for the US DoD, among a larger dataset of recent projects using other lifecycle processes. Results: Statistical results showed that initial software requirements is a valid size metric for estimating agile software development effort. Prediction accuracy improves when peak staff and domain are added as inputs to the cost models. Conclusion: These models may be used for estimates of agile projects, and evaluating software development contract cost proposals with inputs available during the bidding phase or earlier.