New and Improved Tab Rating System
Hey everyone!
We want all tab ratings to be as honest and objective as possible — that’s why we are launching the new rating system. But before the actual launch, we would like to tell you what you can expect from it.
The current system
Through out the years, the average rating of all Ultimate Guitar (UG) tabs has increased:
Average tab rating changes on ultimate-guitar.com from 2005 to 2016
In 2007 the average rating of a tab was 4.1. Currently, it’s more than 4.5. This is pretty cool because it means that tabs have become better.
Although the current system is pretty good, it doesn’t provide enough accuracy. Some awesome tabs have 3.5 or 4 stars, while some poor ones have 4.5. This happens because the system is based on an arithmetic mean and if the tab has only a couple of votes, any additional vote affects the rating of the tab. For example, if someone gives a 1-star vote for a good, but unpopular tab, the rating of this tab immediately becomes worse. On the other hand, if a poor quality tab gets a 5-star vote, it appears to look like a good tab.
The new formula
We found a new formula that increases the accuracy of the rating. This is how it looks:
R — rating of the tab
V — number of votes for the tab
M — minimum number of votes the tab gets to become rated, otherwise it will show up on the website as a tab without rating
r — arithmetic mean (average rating) of the current tab
C — arithmetic mean (average rating) of all UG tabs. Currently C = 4.5.
See the letter “С”. This is a very important letter because it represents how users generally vote. User's votes can be influenced by different reasons. Users may vote because the tab is good, because they love the artist or the song, because they had a bad day or they are excited about the tab. This means many really good tabs may get poor votes just because users might not like the band. Also many tabs of popular songs may get 5 stars just because people love the song but don't take into consideration the quality of the tab. We believe this is unfair. We want all of the tabs to be voted honestly based on quality and not on how much they like or do not like the artist.
Here’s an example of how the new formula works:
A tab has 6 votes, 4 votes ***** and 2 votes *, then R = 6/(6+5)*3,67 + 5/(6+5)*4.5 = 4.04. In the old system you would have it like this: R = (4*5+2*1)/6=3,67.
Why is the new rating of the tab higher when using the new system? It’s because these two 1-star votes are not a normal behavior of our users. The Average rating of 4.8 stars tells us that most tabs are pretty good and that users tend to give high votes. In the new system, tabs with lesser votes are highly affected by the average tab rating. More votes lower this affection and the rating of the tab begins to represent the users’ opinion of the particular tab.
What does it affect
Tab authors' level won't be affected. Although the level of tab authors depends on the average rating of their tabs, the new system won't affect it. If your level is III, you won't be demoted, no matter how the average rating of your tabs changes within the new system.
No fraud. No more 1-star trolling or 5-star rigging. If a tab is not very popular, its rating also depends on the average rating of all UG tabs (which is 4.5), and any bad votes won't decrease the rating too much. And if a tab is very popular and has dozens of votes, one more bad vote against it won't affect the tabs rating.
More objective rating. Since most tabs on UG have a rating of about 4.5, we use this number as a starting point of the tabs' rating. Any vote will increase or decrease the rating, but it takes more than a couple of votes to represent the real users' opinion on the quality of the tab. We think that it takes at least 5 votes to achieve the minimum amount of objectiveness.
Bigger chance for new tabs. The best tabs are not always tabs that get many votes. Sometimes a new tab appears on the website and it's much better that any other tab of the same song. Unfortunately, it's hard for it to get to the top. We believe that the new system will help new great tabs become popular.
Long story short:
More objective rating
Authors' levels won't be affected
No more fraud, trolling and rigging
Greater chance for new tabs to become popular.