Gary Illyes from Google made an interesting comment about why we don’t see more frequent updates of the Panda Algorithm.  He was speaking at SMX Advanced this week during a Google AMA.

The question was about when we would see Panda and Penguin updated, as we have been waiting for them to be updated or refreshed for many months now.  But there is a reason behind why they aren’t able to update it more frequently, such as monthly or at least every 2-3 months.

Illyes revealed that in order to update or refresh, they need to gather data from it.  He said sometimes the data won’t work because there is noise or problems with the data, so then they have to wait another month for more data.

He doesn’t specify specifically what type of noise or problems they can run into when looking at the data as it relates to Panda, just that they data isn’t usable and they need to wait for another month’s worth of data.
We do know that we will be seeing a Panda refresh sometime within the next 2-4 weeks, so it would appear they had a month of great data to use for the new refresh.