Topic 1 of 20 · Part I : Shaping Model Behaviour

Fine-tuning

Fine-tuning turns a general model into a specialist by repeatedly showing it the inputs and outputs that define the desired behaviour.

The control pattern

Data asset

Training examples

Knobs

Example quality, Volume, Task mix, Difficulty, Weighting, Curriculum order

Outcome

Specialised and repeatable model behaviour

Measurement

See how to measure this below

What it is

Fine-tuning turns a general model into a specialist by repeatedly showing it the inputs and outputs that define the desired behaviour. The training examples are the data asset you change: changing them changes what the model learns to notice, how it responds, and which mistakes it avoids.

The knobs are the properties of those examples. Quality controls whether the target answer is correct. Quantity controls how often the model sees a pattern. Task mix determines which capabilities receive capacity. Weighting emphasises high-value or high-risk situations. Curriculum order can move the model from straightforward cases toward difficult edge cases.

Fine-tuning is closely related to distillation when the examples come from a larger teacher model, but the two are not identical. Fine-tuning describes the adaptation process; distillation describes transferring behaviour from a teacher into a smaller student.

The knobs in detail

Each row is one adjustable property of the data asset, and what moving it tends to do.

KnobWhat you adjustLikely effect
Example qualityWhether the target answer is actually correctSets the ceiling on everything learned
VolumeHow often the model sees a given patternControls how firmly a behaviour sticks
Task mixExtraction vs. classification vs. explanationDecides which capabilities get capacity
DifficultyClean cases vs. ambiguous onesTrades routine speed against edge-case reasoning
WeightingLoss weight or sampling frequencyEmphasises high-value or high-risk situations
Curriculum orderSimple examples first, hard ones laterShapes how the model generalises to the tail

Applied: Stocks Assistant

For Stocks Assistant, fine-tuning could specialise a compact model in extracting revenue, EPS, margin changes, guidance, risks and management commentary from earnings materials. Examples should include both clean and difficult cases: companies with non-standard fiscal calendars, restated metrics, non-GAAP reconciliations, missing guidance, conflicting numbers, and call transcripts where the Q&A tone differs from prepared remarks. High-impact fields should carry more weight than stylistic preferences : a factual error in reported EPS matters more than whether a summary uses three bullets or four. The model should also learn to abstain on missing or ambiguous evidence rather than being rewarded for always producing an answer.

How to measure it

Evidence that the knob produced the intended behaviour, rather than shifting the problem elsewhere.

  • Field-level accuracy on the metrics that matter most
  • Unsupported-claim rate and citation alignment
  • Performance across sectors, not just in aggregate
  • Calibration of stated uncertainty against observed error
  • A frozen test set that never enters training
  • Comparison against both the teacher and a simple rules baseline

Common mistakes

Mistaking fluency for accuracy : a successful fine-tune is more correct, consistent and predictable, not merely smoother.

Rewarding an answer for every input, which trains away the abstention behaviour you need most on hard documents.