TensorTau PathToAGI Doing Machine Learning Honestly Level 05

Level 05 · Doing Machine Learning Honestly · Chapter 063

Baselines

How do we know an impressive model is solving the problem rather than merely beating an unnecessarily weak comparison?

1. Start embarrassingly simple

Before a giant neural network, try a useful baseline:

  • mean/median prediction for regression;
  • majority or stratified class predictor;
  • logistic regression;
  • a small tree;
  • a heuristic already used by humans.

A baseline gives the result meaning.

2. Baselines are debugging tools

If a sophisticated model cannot beat logistic regression, possible explanations include weak features, implementation bugs, insufficient data, incorrect metric, optimization failure—or simply that the relationship is nearly linear.

That is valuable information.

3. Strong baselines matter

Beating a deliberately bad baseline proves little. Research compares against credible prior methods under fair settings.

The baseline should receive appropriate tuning and the same evaluation protocol whenever possible.

4. A hierarchy is better than one baseline

naive constant
   ↓
simple heuristic
   ↓
linear/classical model
   ↓
current strong method
   ↓
proposed method

Each rung tells us where complexity begins paying for itself.

What to Remember

A result without a meaningful comparison has no scale. Baselines turn “92%” into an interpretable claim.

Next → Error Analysis: once we know the model is imperfect, which mistakes should we fix first?

Six ways to work the chapter, climbing from explaining it in your own words to investigating it like a researcher. Reading is not enough — this is where the chapter lands.

  1. Explain: Why is a baseline part of scientific reasoning?
  2. Calculate: Compare absolute and relative improvement from 80% to 84%.
  3. Predict: What does it suggest if logistic regression matches a deep network?
  4. Break: Create a leakage feature that lets every model crush the baseline, then diagnose the false victory.
  5. Build: Implement three progressively stronger baselines for one dataset.
  6. Investigate: Compare model complexity, runtime and performance—not performance alone.