How Dramlytics valuations work
Dramlytics summarizes historical whisky auction observations. These are recorded results, not offers to buy your bottle or guaranteed future selling prices.
Which observations are used?
The recent bottle valuation uses observations marked as sold, recorded in GBP, with a sale date in the rolling 36-month window. Asking prices, unsold lots and current bids are not used. Currency values are not converted.
Records with equivalent normalized bottle names can be combined. The matching process compares name tokens within a bounded candidate lookup. It is a name-matching heuristic, not independent verification that every auction lot is identical.
How is the typical auction price calculated?
The typical price is the median of the included prices: the middle price when sorted, or the average of the two middle prices when the number of observations is even. The displayed range is the lowest to highest included observation, not a forecast or a confidence interval.
With fewer than five observations, the existing calculation uses the supplied prices without outlier filtering. With at least five, it first removes non-positive prices. If at least five positive prices remain, it takes the values at zero-based positions floor(n × 0.25) and floor(n × 0.75) in the sorted list as the lower and upper quartiles. It excludes prices outside 1.5 times the interquartile range below or above those values. If that filter would remove all prices, it retains the positive sorted list.
The observation count, median, range and volatility describe that same included set. When observations are excluded, the bottle summary states how many. The latest included sale is an individual observation; when dates tie, the highest observation ID is shown.
How are recent prices and charts treated?
The calculation does not weight a newer sale more heavily than another sale within the 36-month window. Chart and table points group included observations by calendar month and auction source and show each group's median. The bottle view supplies up to 60 recent grouped points; a point may therefore represent multiple sales rather than one transaction.
Volatility is the population standard deviation divided by the mean price, shown as a percentage. It describes variation in the recorded prices, not certainty about your bottle's value.
What if there are few sales, or only older records?
One sale is one piece of historical evidence, not a reliable market estimate. Fewer than eight included observations are treated as insufficient to score confidently. Statistics may still be shown with a limited-history explanation.
When no recent valuation is available, a bottle page can show the count, date range and latest positive historical GBP sold observation from before the 36-month window. It does not calculate a new all-time typical price or describe that older result as a current value. If no qualifying evidence exists, no estimated price is shown.
How does the target-price check work?
With enough observations and an entered target price, the existing check combines how far that price is from the median (65% of its risk score), volatility (20%) and the observation-count band (15%). Thresholds and guardrails turn that score into Good, Neutral or Risky. This is a rule-based comparison, not a probability or financial forecast.
Auction results are not retail valuations
A historical auction result and a retailer's asking price answer different questions. Actual proceeds or purchase costs may vary with bottle condition, packaging, provenance, timing, demand and auction fees. The stored observations do not establish a uniform treatment of fees or delivery costs, so do not assume every recorded price is an all-in cost or a seller's net return.
Use the dates, number of observations and recorded price range alongside your own research. Dramlytics does not guarantee a future sale price.