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From 万代豊 <20525entrad...@gmail.com>
Subject Re: Rating scale
Date Wed, 06 Feb 2013 10:13:45 GMT
Sean
Thanks for your clarification.
I'll also keep in mind about what I need to be carefull with SVD.
Regards,,,
Yutaka

2013/2/6 Sean Owen <srowen@gmail.com>

> Yes that would be valid in the sense that the neighborhood based approaches
> are outputting a weighted average of prices here which is also a price. You
> would have to think about which similarity metrics are meaningful though.
>
> The SVD has a perhaps undesirable behavior here. Because it treats the
> squared error of each datum equally it will tend to pay too much attention
> to large values. A 5% error produces 100 times more squared error when the
> value is large.
>
> Ted I think this is why you say the SVD is bad for count-like data?
>  On Feb 6, 2013 8:28 AM, "万代豊" <20525entradero@gmail.com> wrote:
>
> > Hi
> > I also have a similar question regarding result interpretation based on
> how
> > we provide data to recommender.
> > Typcally , we provide rating data say in scale from 1-5 and get the
> result
> > in the same scale range.(and need to be consistent as Sean points out)
> >
> > If we assume the provided data with other dimension such as sales
> > revenue,price or some other physical dimension and can we still use the
> > recommender output as precdicted sales revenue or simulated possible
> price
> > in the same dimension scale?
> > I'm assuming user-based recommendation here.
> >
> > Looks like SVD recommender is more suitable for this purpose.
> > Apprecaite your advise.
> > Yutaka
> >
> >
> >
> > 2013/2/5 Sean Owen <srowen@gmail.com>
> >
> > > You don't have to fix a scale. But your data needs to be consistent.
> > > It wouldn't work to have users rate on a 1-5 scale one day, and 1-100
> > > tomorrow (unless you go back and normalize the old data to 1-100).
> > >
> > > On Mon, Feb 4, 2013 at 3:56 PM, Zia mel <ziad.kamel25@gmail.com>
> wrote:
> > > > Hi , is there a necessity to have a fix rating scale while running
> > > > recommendations or it can be dynamic based on the users' data ?
> > > >
> > > > Many Thanks
> > >
> >
>

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