In product development economics, approximately what fraction of total product cost is effectively committed by decisions made during the design stage?

Introduction / Context:
Design choices (materials, processes, tolerances, architecture) lock in most lifecycle costs long before production begins. Quantifying this emphasizes the importance of design-for-X methods and early cross-functional collaboration.

Given Data / Assumptions:

• The figure sought is an approximate industry rule-of-thumb.
• Scope includes development and manufacturing cost impacts determined by design.
• We are not calculating exact cost, but recognizing commitment influence.

Concept / Approach:
Many studies and texts cite that a large portion of cost—often around 70–80%—is committed by design decisions. Actual spending occurs later, but flexibility to reduce cost diminishes rapidly as design matures, tooling is ordered, and suppliers are engaged.

Step-by-Step Solution:

Verification / Alternative check:
Conduct a post-launch cost breakdown and trace each cost driver back to design decisions; typically, the majority aligns with early choices, supporting the 70–80% heuristic.

Why Other Options Are Wrong:

• 40–50% / 60–75%: Understate common industry guidance.
• 75–85%: Sometimes cited, but 70–80% is the more widely taught range in foundational courses.

Common Pitfalls:
Confusing committed cost with actual spend; failing to involve manufacturing early; over-specifying tolerances that drive excessive machining and inspection costs.

Final Answer:
70–80%