Why Your Software Cost Estimates Change Over Time and How DevSecOps Data Can Help Reduce Cost Risk

SEI Report
Early software cost estimates are often off by over 40%; this paper discusses how programs must continually update estimates as more information becomes available.
Publisher

Software Engineering Institute

Abstract

Program managers (PMs) must realize that early estimates are likely to be off by over 40 percent and that programs need to continually update estimates as additional information becomes available. It is important to understand how program risks can impact cost estimates. Tracking items—such as the decisions that have not yet been made, stability of the top capabilities needed, and measurements derived from the DevSecOps pipeline—can all help program management offices (PMOs) better understand program uncertainties that can impact estimates and help increase confidence in estimates over time.

Cite This SEI Report

Cohen, J. (2023, September 29). Why Your Software Cost Estimates Change Over Time and How DevSecOps Data Can Help Reduce Cost Risk. Retrieved August 19, 2026, from https://www.sei.cmu.edu/library/why-your-software-cost-estimates-change-over-time-and-how-devsecops-data-can-help-reduce-cost-risk/.

@techreport{cohen_2023,
author={Cohen, Julie},
title={Why Your Software Cost Estimates Change Over Time and How DevSecOps Data Can Help Reduce Cost Risk},
month={Sep},
year={2023},
institution={Software Engineering Institute, Carnegie Mellon University},
url={https://www.sei.cmu.edu/library/why-your-software-cost-estimates-change-over-time-and-how-devsecops-data-can-help-reduce-cost-risk/},
note={Accessed: 2026-Aug-19}
}

Cohen, Julie. "Why Your Software Cost Estimates Change Over Time and How DevSecOps Data Can Help Reduce Cost Risk." Software Engineering Institute, Carnegie Mellon University. Software Engineering Institute, September 29, 2023. https://www.sei.cmu.edu/library/why-your-software-cost-estimates-change-over-time-and-how-devsecops-data-can-help-reduce-cost-risk/.

J. Cohen, "Why Your Software Cost Estimates Change Over Time and How DevSecOps Data Can Help Reduce Cost Risk," Software Engineering Institute, Carnegie Mellon University. Software Engineering Institute, 29-Sep-2023 [Online]. Available: https://www.sei.cmu.edu/library/why-your-software-cost-estimates-change-over-time-and-how-devsecops-data-can-help-reduce-cost-risk/. [Accessed: 19-Aug-2026].

Cohen, Julie. "Why Your Software Cost Estimates Change Over Time and How DevSecOps Data Can Help Reduce Cost Risk." Software Engineering Institute, Carnegie Mellon University, Software Engineering Institute, 29 Sep. 2023. https://www.sei.cmu.edu/library/why-your-software-cost-estimates-change-over-time-and-how-devsecops-data-can-help-reduce-cost-risk/. Accessed 19 Aug. 2026.

Cohen, Julie. Why Your Software Cost Estimates Change Over Time and How DevSecOps Data Can Help Reduce Cost Risk. Software Engineering Institute. 2023. https://www.sei.cmu.edu/library/why-your-software-cost-estimates-change-over-time-and-how-devsecops-data-can-help-reduce-cost-risk/