Not as far as I know. There are a bunch of issues to consider that make it 
difficult to do out of the box. 

We did a time based split for test/training hold-out. trained on 90% of older 
data and ran precision based MAP on the newer held-out data. The timestamp is 
not part of the mahout data flow and so this would be impossible out of the box.

That said, I sure wish we had random hold out precision tests. These are 
included with the in-memory versions and if you can run your data through them 
you will get virtually identical results from my experience. There are many 
caveat's that apply to testing recommenders but given an understanding of them 
the tests are quite valuable. For instance MAP lift does not necessarily 
produce user benefit. A/B tests cannot be replaced by offline tests. We use 
them to do rapid iterations and think of them as a sort of heavy-weight unit 
test.

On Aug 30, 2013, at 6:12 AM, Matt Mitchell <[email protected]> wrote:

Hi,

I thought I asked this question once before but couldn't find the thread.
Is there an out-of-the-box way to evaluate the hadoop/offline
recommendation/similarity data? I found an article showing how to do it
with the parallelALS recommender, but not the recommenditembased (for
example).

Matt

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