In this case where there is different scaling or range, would MAE test be suitable and understandable ? For example, if we have range 1-5 and another 1-20 , to make the same interpretation of MAE we need to divide by the range ? Many thanks
On Wed, Feb 6, 2013 at 4:13 AM, 万代豊 <[email protected]> wrote: > 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 <[email protected]> > >> 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" <[email protected]> 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 <[email protected]> >> > >> > > 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 <[email protected]> >> 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 >> > > >> > >>
