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From Jake Mannix <>
Subject Re: Feedback on provided recommendations
Date Tue, 27 Apr 2010 19:46:20 GMT
Another approach would be, if you have a lot of negative feedback as well
as positive feedback, to train two models, both treating the feedback as
and then blend the results with a negative blending weight (i.e. subtract
off a
scaled multiple of the negative feedback recommendation score from the
positive feedback recommendation score).

This would only work if you had enough negative feedback to build an full
model out of it.


On Tue, Apr 27, 2010 at 11:43 AM, Ted Dunning <> wrote:

> Boolean recommendations makes the assumption that either negative feedback
> is really positive feedback (controversial, but works reasonably) or that
> negative feedback is not very useful (also controversial, but actually
> generally true).
> If you really want to use negative information soundly, you need to use a
> much fancier algorithm.  This can lead to huge costs in CPU and memory and
> it may or may not help you.  More practical is to use boolean
> recommendations for the positive side and then just add a few heuristics
> for
> the negative side.  Typical heuristics include:
>  - don't show items that a user has negatively rated (obviously)
>  - don't show items from a source that the user has rated negatively
> several times without rating other items from that source positively
> On Tue, Apr 27, 2010 at 10:27 AM, Tolga Oral <> wrote:
> > We are building a system on top of provided recommendations allowing user
> > to
> > provide feedback. I have a question on how to apply the negative feedback
> > for both boolean and none boolean scores.
> >
> > Assuming its a boolean item (item with no score), I cant see how we can
> > provide negative feedback for a given recommendation. Does this mean we
> > should convert our boolean items to a score of 1 and give score of -1 (or
> > 0)
> > for recommendations that user didnt like?
> >
> > This applies to items with score too I am not sure if the correct way of
> > going about this is to provide 0 or a negative value.
> >
> > Thank you.
> >

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