After using phrase pump for a couple of months it is clear there are problems with the algorithm. It is far too pessimistic about how well words have been learned.
From all accounts it seems Phrase Pump uses the Ebisu algorithm.
-Update! Learning Stages, Flashcards, All Words Panel, PhrasePump, API..
David_Wilkinson “Item reviews are scheduled using the advanced library ‘Ebisu’.”
The ebisu algorithm is flawed (see e.g. Ebisu assumes that half-lives do not change after reviews · Issue #43 · fasiha/ebisu · GitHub). It performs terribly compared to other algorithms (see e.g. GitHub - open-spaced-repetition/srs-benchmark: A benchmark for spaced repetition schedulers/algorithms).
Other people have raised issues caused by this in this forum:
-PhrasePump algorithm
jtsoftware “it seems it is staying on the same words for a long time”
Renn Raven “I think I have a similar problem”
cb83 “agree with you completely”
-Can someone please explain the Phrase Pump algorithm to me.
cb83 “I still keep seeing that word/card/phrase very regularly”
Andy_m “I agree with all the above”
-Make PumpPhrase actually useful?
Twice22 “appear to be useless as always the same words appear”
I would like a functioning phrase pump. I think the concept is very good and it supports minority languages like my target language.
If I can help by implementing a different algorithm then let me know. It could be possible to do without sight of the existing code if you provide an interface.
Best wishes