SRS Benchmark (open-spaced-repetition)

Author: Open Spaced Repetition community (Jarrett Ye et al.) · Type: practitioner · Status: draft · URL: https://github.com/open-spaced-repetition/srs-benchmark

Licence: Open-source GitHub repository; results tables freely quotable with attribution

Summary

A continuously maintained public benchmark of spaced repetition algorithms evaluated on data from 10,000 Anki users comprising roughly 727 million reviews (about 350 million after filtering, without same-day reviews). Algorithms are compared on log loss, calibration RMSE, and AUC using time-series splits to prevent leakage. FSRS variants sit at the top of the practical (non-neural) leaderboard; only heavyweight neural models such as RWKV-P beat FSRS-7, and classic SM-2-family schedulers rank far lower. This is the citable practitioner evidence that FSRS is currently the best openly available scheduler class Immersive could have chosen, and Anki has shipped FSRS since version 23.10.

Insights

• FSRS is validated on one of the largest public review datasets in existence: about 727 million reviews from 10,000 Anki users, evaluated with leakage-safe time-series splits. (medium, draft) fsrs spaced repetition benchmark

  Paraphrase: the benchmark evaluates algorithms on ~727 million reviews from 10,000 users, using ~349.9 million reviews after filtering when same-day reviews are excluded. — README, dataset section

• FSRS-7 achieves log loss 0.3437 on the benchmark, with only large neural models (RWKV-P at 0.2773) predicting recall better, while legacy SM-2-style schedulers rank far below. (medium, draft) fsrs benchmark spaced repetition

  FSRS-7: 0.3437±0.0043 (Log Loss); RWKV-P: 0.2773±0.0036 (Log Loss) — README, results table (without same-day reviews)

• FSRS has been adopted by Anki (shipped since version 23.10, late 2023), giving it mainstream credibility Immersive can reference when explaining its scheduler choice. (medium, draft) fsrs positioning spaced repetition

  Paraphrase: the fsrs4anki project documentation states Anki adopted FSRS as a built-in scheduler in version 23.10 (November 2023). — Related fsrs4anki wiki