Part 4 · 1 chapters · ~10 min

Trade Studies

A structured comparison of three ways to generate clearance letters: criteria and weights agreed first with residency as a hard gate, evidence-backed scores, weighted totals, a sensitivity check that turns a tie into a product question, and the decision recorded with conditions to reopen it.

Structured comparison, weighting and the decision record

decide once, explain forever

The question and the real options.
Criteria and weights agreed first. Hard gates are kept separate from weights.
Scores backed by evidence.
Weighted totals (C 4.50, A 3.70, B out on the gate).
Sensitivity: does the winner survive reasonable changes to the weights?
Record it in an ADR, including what would reopen the decision.

code

// the arithmetic, and the sensitivity check, in a few lines
const criteria = { correctness: 0.30, ops: 0.20, latency: 0.15, residency: 0.15, cost: 0.10, flexibility: 0.10 };
const options = {
  A: { correctness: 4, ops: 2, latency: 3, residency: 5, cost: 4, flexibility: 5 },
  B: { correctness: 4, ops: 5, latency: 4, residency: 1, cost: 2, flexibility: 3 },
  C: { correctness: 5, ops: 4, latency: 5, residency: 5, cost: 5, flexibility: 2 },
};
const gates = { residency: 3 };                                   // must score at least 3
const score = (o: Record<string, number>, w = criteria) =>
  Object.entries(gates).some(([k, min]) => o[k] < min) ? null : Object.entries(w).reduce((s, [k, wt]) => s + o[k] * wt, 0);

score(options.A); score(options.B); score(options.C);           // 3.70, null, 4.50
const flexHeavy = { ...criteria, correctness: 0.10, flexibility: 0.30 };
score(options.A, flexHeavy); score(options.C, flexHeavy);         // 3.90, 3.90 → depends on how much layout matters

the failure mode

Scoring the options first and then choosing weights produces whatever answer the strongest voice wanted, now with a table to back it. Ask for the weights in writing before anyone sees a score. That one ordering rule is most of the value of a trade study.

A TRADE STUDY

criteria and weights agreed first, options scored against them, the winner tested for robustness, the decision written down

swipe the figure sideways, or tap expand for full screen

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the question

The question: how should clearance letters be generated? Option A: an HTML template rendered to PDF by a headless browser in the service. Option B: a managed document-generation SaaS. Option C: a PDF library generating the document directly in code.