AI engineering glossary · Feature engineering data prep
What is LOCF (last observation carried forward)?
Last observation carried forward (also called LOCF, Forward fill): An imputation method for time-ordered data that fills a gap with the most recent earlier observed value. It is simple and never uses future data, but can hide real change and bias trends.
Last observation carried forward: an example
If a sensor reports 24 degrees at 10:00 and nothing at 11:00, the 11:00 reading is filled as 24.
Related terms
More Feature engineering data prep terms
- Leave-one-out encoding
- Lemmatization
- Listwise deletion
- Log transform
- Mahalanobis distance
- Max-abs scaling
- Mean imputation
- Median imputation
Where you learn it
Last observation carried forward is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.