Millisecond Forums

Does Maxrunsize override poolsize?

https://forums.millisecond.com/Topic15585.aspx

By Kolfers - 2/23/2015

Hi! 

I have a quick question, say I have the following list: 

<list list_target_2_side>
/ items = ("A", "B", "C")
/ poolsize = 9
/ maxrunsize = 2
/ selectionrate = always
/ selectionmode = random
</list>


Will the maxrunsize (if needed) override the specified pool to fullfil the constraint? That is, could it be that I end up with a total of 4 x A, 3x B and 2xC after 9 trials, instead of 3xA, 3xB, 3xC. 

Or does the maxrunsize get overridden by the pool, and do I always end up with 3xA, 3xB and 3xC, with the possibility that there can be 3 consecutive stimuli (eg. C - C - C)?

Thanks!

Kerwin
By Dave - 2/23/2015

The poolsize is what you specify it to be -- it does not come into play with regards to sampling constraints. Beyond that, the documentation for /maxrunsize details exactly how constraints are dealt with when they cannot be satisfied:

"Random selection is done on the fly, so if multiple selection constraints such as not or replace are in place, it may not be possible to satisfy them all on a give trial, especially if there are only a few remaining items in the selection pool. In that case, the list will suspend one of the constraints and try again. If it still can not satisfy the remaining constraints, it suspends another and tries again, and so forth. By default, the maxrunsize constraint is suspended first, then replace, and finally the not constraints."