I read anki manual on changing interval modifier. I am creating a new deck and want low retention of 60% - so out of experience I would want to start with an interval modifier of 130% ( just a gut call).
Let us assume after 30 days I find my retention to be 75% and hence need to increase my interval modifier again.
So as per manual it will be log(60%)/log(75%) = 1.77 - Now should my new interval be 177% or 177*130%
I am asking this because I started with a base of 130% instead of 100%.Will the formula take care of the base change or I have to multiply it with the 130%? Could you please explain the science behind this briefly if possible - just for an intuitive idea?
Thanks a lot in advance
Relevant parts of manual:
On the SuperMemo website, they suggest that you can find an appropriate multiplier for a desired retention rate. Their formula boils down to:
log(desired retention%) / log(current retention%)
Imagine we have a current retention rate of 85% and we want to increase it to 90%. We’d calculate the modifier as:
log(90%) / log(85%) = 0.65
If you plug the resulting 65% into the interval modifier, you should find over time that your retention moves closer to your desired retention.