Definition
Plain language
An open-weight language model family from the Allen Institute for AI.
As stated in the literature
AI2's fully open-source foundation model series, with weights, training data, and recipes all released; used as a backbone in EvoLM and other open research work.
Also called: OLMo-3, OLMo-Hybrid
Why it matters: Releasing data and recipes alongside weights makes serious scientific study of language models possible outside of frontier labs.
For example, a researcher can download OLMo's weights and the exact training data used to produce them to reproduce a finding.
Heard on the show
“You take a rubric generator that was trained against a one-point-seven-B chwen judge, and at inference time you swap in a totally different judge — an eight-B chwen, an OLMo model, a Mistral.”Episode 019 — When the Best Reward Model Trains the Worst Policy: Inside EvoLM