midPCA

What is reconstruction error in PCA?

Updated May 17, 2026

Short answer

Reconstruction error measures information loss after dimensionality reduction.

Deep explanation

When data is projected into lower dimensions and reconstructed back, difference between original and reconstructed data is reconstruction error. Lower error indicates better retention of information.

Real-world example

Evaluating compression quality in image processing.

Common mistakes

  • Ignoring reconstruction error when selecting components.

Follow-up questions

  • What reduces reconstruction error?
  • Is zero error possible?

More PCA interview questions

View all →