In updating the Hall of taps with new craft beer ratings, and starting to clean up the data we realized that the Hall Rating needed an update from the original version.
When we came up with the original formula for the Hall of Taps there were beers that had negative hall ratings. Well, either the beers are that bad OR our hall rating was bad. After crunching some numbers and doing some analysis, we realized there really were some craft beers that were that bad.
So the first thing we did was scrub the hall of taps of craft beer that had hall ratings either negative or of zero. We don’t want beers that dont have a rating (or have a negative one). The next thing we did was completely overhaul how we formulated the hall rating for a craft beer.
The first key to the Hall Rating is called TAP, it doesn’t really stand for anything it’s just a beer related term that’s a cool placeholder. When you’re looking for a beer, say you drink it and you like it-so you ask your go-to craft beer aficionado for a similar beer because you liked the beer you had. That’s what we are trying to achieve with the TAP.
Of the craft beers we have in the database we look at the top 29.4% (similar to WAR in baseball) as a ‘replacement beer’ so if you’re drinking an American IPA we have determined a ‘replacement beer’ is Shreddin Red. Other American IPAs can be either better or worse than it. We then take a craft beers Untappd rating minus the replacement beer’s Untappd rating and multiply it by 1.8. It looks like so:
TAP = 1.8 * (rating – replacementBeer)
The 1.8 comes from something the Hall of Stats uses in their formulas. For any craft beer, this gives up how it stacks up against other beers of its style.
The next thing we did was look at check-in. Now, mass-produced beers have more check-ins that craft beers that aren’t as well known (or as produced as much so decided to use Log10 to ensure that Untappd check-ins are weighted the same, which looks like this:
Volume = Math.Log10(checkins)
Now, we needed some sort of scale to determine what a perfect hall rating would be. Going back to the Hall of Stats, we are big Detroit Tigers Fans. Ty Cobb is arguably the greatest player in Tigers history and has a hall rating of 320. So we are going to use that as our benchmark for a “perfect beer”. So a perfect beer (in our minds) is going to have a 5.0 rating over 1,00 check-ins on Untappd.
SCALE = (320 / Math.Log10(1000)) / (5 – replacementBeer).
Now that we have the three pieces of our puzzle together. We have a final formula of:
Hall Rating = TAP * VOLUME * SCALE
As the Hall grows we will continue to make changes to the formula, but we think its already better than the first version we put out.