I've cracked the question about lots of 1-2 ratings. It's someone who would
like to see all photos.*There's no "Skip to next photo" button.*


On first view, it took a while to find the voting buttons. If they're the
primary action, maybe they could be more prominent, perhaps stronger colour?

I didn't notice any guidelines on how to vote, i.e. not judge the
photographer? If you want me to read that, put it nearby the voting buttons.

Both my ratings were 3:s because using a laptop trackpad, and having seen 0
or 1 photos before, I couldn't really use the full scale. Neither would I
feel very inclined to judge one such a fine scale as 10 steps. (I'm biased
on this: At work, our questionnaires use 5-grade scale, and our respondents
are both pushed by their bosses and sent reminders to make them fill in
those questionnaires.)

Also; Max Diff FTW! I'm very grateful to have learned about that today.

Cheers
/Simon B.


On Wed, Apr 8, 2009 at 1:17 PM, Rowland Shaw <[email protected]> wrote:

> Don't forget that "time of year when photo was taken" affects the
> results -- snowy scenes taken might beat "photo of a road on a dull
> drizzly day, taken only to fill up the Geograph grid", and whilst
> there is guidance to not rate the photographer, a good composition
> will enhance the view;
>
> As an example; two photographs taken at the same locale, by the same
> person, within a few minutes of each other, pointing in different
> directions:
> http://www.flickr.com/photos/ratarsed/3377071312/
> http://www.flickr.com/photos/ratarsed/3376131577/
>
> Both photos have their artistic merits, but in my mind, one is a lot
> more scenic than the other -- so how should this affect the ranking of
> that area?
> (For reference, if I saw these on ScenicOrNot, I'd rate one as a 3,
> and the other as an 8)
>
>
> 2009/4/8 Francis Davey <[email protected]>:
> > 2009/4/8 Frankie Roberto <[email protected]>:
> >>
> >> I'd be fascinated to know how a factor analysis works (I tried looking
> at
> >> http://en.wikipedia.org/wiki/Factor_analysis, but it's not the most
> >> accessible Wikipedia page).
> >
> > No, its awful.
> >
> > I'm using the term a bit generically but its quite simple.
> >
> > Eg, imagine there are N people who have voted on pictures. Now take an
> > N dimensional graph and plot where they rate them all (or how they
> > compare them all). Each picture is a point in this N-dimensional
> > space.
> >
> > Now we have an utterly incomprehensible graph which is also hard to
> > visualise to those of us who find thinking in more dimensions than we
> > have toes difficult.
> >
> > So, what would be great is to somehow reduce that number of dimensions
> > a bit, or even a lot. That amounts to finding a few factors that
> > explain most of the data.
> >
> > How you do this, like much of stats, depends. There are lots and lots
> > of algorithms for it. Some are easy - roughly corresponding to
> > projecting the N-dimensional space down onto some subspace that's more
> > manageable, so all you have to do is find the subspace. But there's no
> > reason to assume that everything is linear, so you might do something
> > more sophisticated.
> >
> >>
> >> Another alternative might be to force people to make a binary choice
> between
> >> "scenic" and "not scenic", or perhaps a 4 way choice with 2 "very"
> options.
> >> Then you avoid all the indecisive 4-6 responses.
> >>
> >
> > If what you want is a *lot* of data comparisons fast then use
> > something like Maxdiff:
> >
> > http://en.wikipedia.org/wiki/MaxDiff
> >
> > Show four photos and ask for best and worst. That's still amazingly
> > easy (almost as easy as the kittenwar game) and you get a lot more
> > ratings done.
> >
> > But, beware! In this case there's a whole nother issue. So far we have
> > been considering:
> >
> > - finding scenic places on the basis of some mass voting (a million
> > people can't be wrong)
> > - finding places I'd like (needs a factor analysis or something similar)
> >
> > But the scenes have location data too. You might want to say here ->
> > is an really good place to go because there is a cluster of scenically
> > rated photos from there. That requires a whole lot more sophisticated
> > analysis again.
> >
> > However I don't know what the use cases of this data might be, so
> > can't comment. I'm not saying Tom et al. are wrong because they know
> > what their constraints and aims are which I most emphatically do not.
> > What's more they have almost certainly taken the advice of
> > statisticians to get this just right, so my rather amateurish
> > criticism is meant to be just that, my half pennyworth.
> >
> > When I get stuck, I tend to go off and talk to a fellow of the royal
> > statistical society. It tends to unstick my mind, though I usually
> > come away realising how much more problematic everything really is
> > 8-).
> >
> > --
> > Francis Davey
> >
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