Short Answer

Why Dev and Test Sets Should Match

Question: In one to three sentences, explain why a dev/test gap is easier to interpret when both sets come from the same distribution.

Sample answer: If the dev and test sets are drawn from the same distribution, a score gap between them is less likely to be caused by different data. That makes dev-set overfitting the most plausible explanation for the difference.

Key points:

  • Matching distributions removes data shift as an alternative explanation.
  • The remaining gap can then be attributed to overfitting on the dev set.

Rubric: The answer should explain that using the same distribution for dev and test removes distribution mismatch as a competing cause and makes dev-set overfitting the clear diagnosis.

0

1

Updated 2026-08-12

Contributors are:

Who are from:

Tags

Machine Learning

Deep Learning

Machine Learning Strategy

Supervised Learning

Dive into Deep Learning @ D2L

Data Science

Machine Learning Yearning @ DeepLearning.AI