NPI, DFM/DFA & Engineering Change worked example

Engineering Change Cost at 50% disposition share reworked: a worked example in npi, dfm/dfa & engineering change

This worked example runs the engineering change cost numbers for a tougher week than the baseline: 50% disposition share reworked instead of the typical 70%. Estimate the full cost of executing an engineering change, including part disposition and the administrative overhead of the ECN.

The inputs for this scenario

  • Affected Parts in Field: 850 parts (held at the documented default)
  • Rework Cost Per Part: 12.5 $/part (held at the documented default)
  • Disposition Share Reworked: 50 % (the input this scenario stresses; the baseline uses 70)
  • ECN Administration Cost: 3,500 $ (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: ECN cost = affected parts x rework cost per part x disposition share% + administration cost.
  • Total engineering change cost works out to 8,813 $ at these inputs, and this is the headline figure for the scenario.
  • Engineering change cost per unit works out to 10.37 $ / piece at these inputs.
  • Variable engineering change cost works out to 5,313 $ at these inputs.
  • Fixed engineering change cost adder works out to 3,500 $ at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where disposition share reworked sits at 70% and the headline result is 10,938 $, this scenario comes in 19.43% below the baseline at 8,813 $.
  • Use it at change board review to decide between immediate implementation, run-out, or deferral, and to compare the cost of competing change strategies. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • Total engineering change cost: 8,813 $ (headline result)
  • Engineering change cost per unit: 10.37 $ / piece
  • Variable engineering change cost: 5,313 $
  • Fixed engineering change cost adder: 3,500 $

Run it with your numbers

  • To rerun this with your own numbers, open the live Engineering Change Cost calculator, set disposition share reworked to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.