Minimum recommended retention : days to simulate

[possopo]

hi,

here is what I found for my own set of cards* when I’m computing the minimum recommended retention and I’m tweaking with the number of days to simulate (my cards are languages only so I’d like to remember words FOREVER).

simulate X day : minimum recommended retention
10 days : 0.88
15 days : 0.93
30 days : 0.94
60 days : 0.91
100 days : 0.88
150 days : 0.91
200 days : 0.88
300 days : 0.91
365 days (default setting) : 0.89
500 days : 0.89
1000 days : 0.91
2000 days : 0.91

it looks pretty inconsistent, is there a reason for that ?

*if that helps, here are some details of my decks :
14000 cards learned
20000 waiting (I decided to stop Russian for now until the number of daily reviews declines quite significantly)
about 10 new cards per day
desired retention rate : 0.9
my retention rate : 90% last week, 88% last month, 89% since the beginning (with two big decks at 91% and two smaller ones at around 84%

happy new year to you all !!!

[sorata]

@possopo

it looks pretty inconsistent, is there a reason for that ?

It’s just noise. I think you can go with something like .92 as DR.

[szalejot]

Simulation can be inconsistent for a small number of days.
You can notice, that it gets consistent for 300 days or more - answers in a range 0.89-0.91 are quite close.