How do you compare two floorplans without cherry-picking metrics?

Short Answer

The core discipline here is simple to state and easy to violate under deadline pressure: decide what you're measuring and how you're measuring it before you look at which floorplan wins on that metric — otherwise you'll unconsciously pick the metrics that favor whichever option you already prefer. Build one scorecard with declared, written-down definitions for area/utilization, usable-row count, macro legality, channel feasibility, pin constraints, congestion, PG reservation, voltage-area legality, early timing, and change risk — and apply the exact same measurement method to both floorplans.

Technical Explanation

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• Record the measurement settings alongside every number — what tool mode, what scenario, what effort level was used to generate each metric — because a favorable number produced with looser settings than its competitor is not a fair comparison.
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• Finally, test sensitivity to expected design growth — a floorplan that wins narrowly today but has much less margin for the design's expected growth is a worse long-term choice even if this round's scorecard looks close.

Formula Or Decision Rule

Decision rule: reject hard stops, then choose the lower owned risk across project priorities.

What To Check

• Warning sign: Each advocate reports only the metric their option wins.
• Inspect: choose one affected region, macro, row, pin, path, or net and trace the physical cause.
• Correct: Recompute the full scorecard and require explanations for every material delta.

Healthy, Suspicious & Hard-stop Results

• Healthy: Use one scorecard with declared definitions and identical methods for area/utilisation, usable rows, macro legality, channels, pins, congestion, PG reservation, voltage areas, early timing, and change risk.
• Hard stop: required legality or physical feasibility is missing or unexplained.

What The Interviewer Is Testing

” to measurable physical evidence and an owned correction.

Follow-up Question & Model Response

"* Candidate Model Response: Model response: “I would change it if the same controlled rerun shows that each advocate reports only the metric their option wins. ”