Page 6 of 8~104 min topic

Choosing a model

Evaluate with evidence

Measure model selection with denominators, slices, and gates chosen before seeing results on the invoice-extraction service.

~13 min this pageEvaluation

1Learn the idea

Read

Metrics

Track for model selection: field-level F1, schema-valid rate, $/1k docs, p95 latency, truncation rate, fallback success. Report fractions like 36/40, not vague quality adjectives. Segment by language, plan tier, document length, or other slices that matter for the invoice-extraction service.

Read

Protocol

Freeze inputs and neighboring versions while evaluating model selection. Change one control. Pair results case by case on the invoice-extraction service. Define hard gates (severe errors, privacy, latency) before the bake-off. Use deterministic checks where possible; humans for nuance; model judges only with calibration against gold.

Numeric reminder for model selection: If model L hits 96% field-F1 at $0.12/1k docs and model H hits 97% at $0.55/1k, the +1 pt may lose unless errors are extremely costly.

Read

Make it operational

Resist adding a twelfth metric before the first three for model selection on the invoice-extraction service have owners. This workload improves faster when a small scorecard is trusted than when a warehouse of unused plots exists.

Also pin one numeric memory from this model selection chapter: If model L hits 96% field-F1 at $0.12/1k docs and model H hits 97% at $0.55/1k, the +1 pt may lose unless errors are extremely costly. That number is not decoration; it is a template for how claims about model selection on the invoice-extraction service should look in design docs. Scoped specifically to model selection / invoice-extraction service / evaluation.

Read

Common mix-ups

People confuse model selection with neighboring buzzwords when debugging the invoice-extraction service. Before changing prompts, ask whether the broken stage was evidence gathering, the model selection judgment itself, validation, or the product action. Fixing the wrong stage creates folklore (“we tried model selection and it failed”) that blocks the next team on the invoice-extraction service. Scoped specifically to model selection / invoice-extraction service / evaluation.

Read

Rehearsal (choosing-a-model/evaluation)

Write a five-line artifact for this page: goal, inputs, check, owner, stop rule. Invent one fluent failure that the check would catch. Keep details specific to choosing a model rather than generic AI advice.

Read

Rehearsal (choosing-a-model/evaluation)

Write a five-line artifact for this page: goal, inputs, check, owner, stop rule. Invent one fluent failure that the check would catch. Keep details specific to choosing a model rather than generic AI advice.

Read

Rehearsal (choosing-a-model/evaluation)

Write a five-line artifact for this page: goal, inputs, check, owner, stop rule. Invent one fluent failure that the check would catch. Keep details specific to choosing a model rather than generic AI advice.

Read

Rehearsal (choosing-a-model/evaluation)

Write a five-line artifact for this page: goal, inputs, check, owner, stop rule. Invent one fluent failure that the check would catch. Keep details specific to choosing a model rather than generic AI advice.

Go deeper

Before you start

Why this matters

A demo of the invoice-extraction service looks great on three hand-picked examples of model selection. What does that demo refuse to tell you?

Check your understanding

Page assessment

Answer from memory. Completion is saved from this evidence, not from opening the next page.

1. What is one idea from this page you would apply, and what evidence would you check?

All responses are required.