Average rating bug

I've just noticed that there seems to be a bug with the average rating for albums. I was just browsing the top albums in death metal and noticed this.

Yes I know that, but surely by that logic the Obscura album should be rated higher since it has 4 collab reviews and the Entombed album just has 4 ratings and no reviews?

Edited by adg211288 - 07 Apr 2011 at 8:33am

Well when I go to the page now there are 5 ratings: 2 five stars, one 4.5, one 4, and one 2.5 and the average is 4.83. However, one of the five stars is by Vic, who is a collab. That average works correct if you give his rating the 20x collab weight. I tested a few other albums around  and I know at least this one is the same, so it's not just albums without reviews. Testing this was very annoying because I had to hover over names on the ratings to see who was a collab, so I don't remember which other ones I did, and I didn't do an extensive search because it's almost 3am and I couldn't be bothered. Some of my tests made no sense, but I think that was probably just mistakes on my part. 

Maybe it has always been this way the whole time and nobody noticed until now? Oops.   

Edited by Henry Plainview - 09 Apr 2011 at 2:54am

adg211288 wrote: I was under the impression that the weighting only applies if there is a review, a rating always just being a rating regardless of whose rating it is. Actually I was also under the impression that the weighting didn't actually apply to the average shown on each album, just how the top lists on each genre page were decided, after all if the weighting applies to the average then by that logic the top album in each sub should be the one with the highest average, which isn't the case in every sub.

A rating only is supposed to be 1 weight no matter who is giving it, but clearly something has gone awry. 

The weighting absolutely applies to the displayed average, the whole point is for the sober collab reviews to outweigh a lot of ratings only from random people so people have a more accurate picture. That's something that can be easily verified with a calculator.

The placement on the list is considering the weight and the average relative to the other albums and is a little bit harder to do by hand because I think you would have to calculate the weight of every album in the list you're talking about. But your problem is that you are assuming the albums with the most weight from reviews and ratings are also the highest rated. That is clearly not always the case. i.e. The difference in weight between Ziltoid the Omniscient (with 4 collab reviews and a member review and more ratings only) and Fear of a Blank Planet (only 3 collab reviews) is greater than the .04% difference in their overall average. 

Edited by Henry Plainview - 09 Apr 2011 at 4:41am

Ok, I understand it better now. Thank you Henry.

I'd say yes because going back to the two albums I posted about originally, Obscura's album has 4 collab reviews which should have 20x rating weight each, whereas the Entombed album has no reviews at all, yet clearly has a higher weight rating/placement on the list.

UMUR wrote: I�ve always had trouble with the math, so educate me here. Is there a problem that needs to be reported or not?

Yes, it appears that some (perhaps even all) collab ratings are receiving the 20x weight even though there is no review. Only the collab reviews should be weighted 20x, everybody's rating without a review is supposed to be equal (1x). 

(Sorry to repeat but I thought adg's explanation was not very clear)

If collab rating only is actually worth 20x, then those averages are actually working out correctly right now, despite consistently higher ratings for Obscura and more collab reviews/ratings than Entombed. Doesn't seem right, but I guess you can't argue against the maths. So now that's cleared up I'm doubting there is a bug with the average ratings after all.

The Angry Scotsman wrote: According to Phil, (and I'm pretty sure he'd know ) collabs get the 20X weight, review or rating only. So yeah, I'll leave the math to you guys but that is the case. Guess another perk of collabhood.

Ok, well then why is it like that on MMA but not PA? It used to be like that on PA, but Max changed it because it's a terrible idea, so why go backwards? 

Also, I thought you were still on break from the internet???