I do - although I can take no credit for it. It came from a CellarTracker discussion thread.
QPR=LN(EXP(Rating)/Price) + 2.7*TargetPrice/Price + (Rating/TargetRating-1)*10
The formula is for use in an Excel spreadsheet and attempts to account for the non-linear nature of the scale, i.e., the difference between a wine with an 85-score and an 89-score is not the same as the difference between a wine with an 89-score and a 93-score, which again is not the same as the difference between a 93-score and a 97-score or between 97 and 100.
In my case I use $20 as the target price and 90 points as the target rating. Using the formula, a 90 point wine that cost $20 returns a QPR of 89.70. So, anything about that has a good QPR to me (DTQPR). A 100 point wine that cost $20 would return a 110.82 DTQPR. However, the formula doesn't really measure the pain related to cost. For example, a 100 point wine that cost $2,500 would return a DTQPR of 93.31 - above my "neutral" QPR of 89.70 but also (well) above what I would consider spending on a bottle of wine. And a 95 point wine that cost $38.50 would return the same DTQPR of 93.31.
So its not perfect, but it's consistent and provides relative scores by which to evaluate our habit...
Much more debate at
Cellar Tracker Forum
