Why traditional cost models fail in dynamic programs
Understand the structural limitations of spreadsheet-based estimating when requirements change frequently and late-stage scope shifts invalidate early assumptions.


Tom Shanahan is the founder and CEO of ProjStream, a digital platform that helps government contractors and engineering firms reconnect their requirements, estimates, and program outcomes.
With over two decades of experience in defense contracting, systems engineering, and enterprise software, Tom has led transformation initiatives for Fortune 500 defense contractors and helped engineering-intensive organizations modernize their estimating and program control workflows.
Prior to founding ProjStream, Tom held leadership roles in cost engineering, digital transformation, and business development at major aerospace and defense firms. He holds degrees in systems engineering and business administration and has published extensively on the intersection of requirements management, cost estimating, and AI-driven decision support.
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ProjStream is a digital platform that helps government contractors and engineering firms reconnect their requirements, estimates, and program outcomes through version-aware tracking and intelligent automation.
Built specifically for estimating teams, program controls professionals, and digital engineering leaders, ProjStream’s PrecisionAI module delivers scope-sensitive cost attribution, automated change intelligence, and real-time impact analysis—enabling teams to move from reactive cost management to proactive decision support.
Trusted by defense contractors, systems integrators, and engineering-intensive organizations, ProjStream integrates with existing ERP, PLM, and requirements management systems to create a unified digital thread from requirements to cost.