SleeperLot

How a number is made

Written so you can check us. Every figure on this page comes from the last scored day (—, —) and is fetched from the same file the track record renders.

1. What we are actually looking for

Not underpriced — under-attended. Every auction looks cheap until it closes. An auction only ends below market when price discovery fails: nobody qualified saw it, the title was bad, it closed at 4am, the category is thin. So the thing we rank on is low attention on an item we can independently value. A lot with forty bids is correctly priced by definition, however cheap it looks with an hour to go.

That makes identity, not price, the binding constraint. If we cannot work out what an item is from its title, no amount of quiet tells us anything.

2. The matching ladder

Every listing is matched to a cluster of comparable items. The rung it lands on determines what we are allowed to say about it.

RungMatchConfidenceWhat we do
1Exact identifier — EPID, MPN, cert numberHighScore and alert
2Same model, different conditionHigh, adjustedScore and alert
3Brand + category + attributesMediumScore and alert
4Category onlyLowScore, never alert
5No usable matchNoneSay nothing

Rung 5 is the important one. A lot we cannot identify is not a cheap lot, it is an unknown lot, and the honest output is silence. The gate is mechanical — rungs 4 and 5 cannot reach an alert regardless of how large the apparent discount is.

3. Why we decline most of them

On the last scored day we declined — of — closes — — of the day — and scored the remaining —.

That number is the product working, not failing. Most auction titles do not contain enough to identify the item: no model number, no brand, no attributes that pin it to anything priceable. A tool that produced an estimate for all of them would be producing noise for three quarters of its output, and false positives here cost you money rather than attention. We would rather miss half the good lots than surface junk.

4. The three prices, kept apart

Conflating these is the most common mistake in this category, so they carry separate labels everywhere on the site and never substitute for each other.

NumberMeansWhose number
predicted close What the auction ends at What you pay
cheapest BIN What it would cost to just buy one now The buyer’s reference
expected sold What you would receive reselling it The reseller’s reference — not published yet

A Buy It Now price is an ask, not a transaction. Active BIN pools are survivorship-skewed: correctly priced items sell and leave, overpriced ones sit forever, so the median ask drifts above real market value. We therefore use the 10th percentile of the credible BIN pool, not the median. For a buyer that is conservative in the right direction — your real alternative genuinely is somebody’s asking price. For a reseller it is not good enough, which is why no margin figure is published until there is a fee model and sold comps behind it.

Where a market has no active BIN pool at all, the reference is instead a leave-one-out comp: the 10th–90th percentile of what the other items in the same cluster closed at. The lot’s own price is never in the pool that priced it. Being under that is a weaker claim than beating a live asking price, so it is labelled under typical close rather than buyer savings.

5. What the interval means

Predictions are published as ranges with a sample size, never as a single number. Two reasons, and neither is stylistic:

On the last scored day, — lots closed under the cheapest credible ask for the same item, a total of — with a median of —. Every one of those figures is measured against an asking price, so read it as what a buyer avoided paying rather than as a profit.

We do not yet publish a predicted closing price for this venue. Predicting the hammer needs a pool of comparable closes deep enough to build a range from, and eBay’s clusters are not there yet — so rather than quote a range we cannot stand behind, we quote none, and the track record shows what each lot actually sold for instead. When that changes, the calibration of those ranges gets published here in full, misses included.

5b. Shipping is quoted to one reference location

Many sellers price shipping by weight and destination, so there is no single correct figure: eBay cannot quote one without knowing where the buyer is. Rather than leave those blank, we ask for the cost to one fixed reference location in the central United States and publish that. It is the same location for every lot on this site.

Your shipping will differ. If you are far from the middle of the country, a weight-priced item costs you more than the figure shown, and the saving shrinks accordingly. Shipping is quoted at collection time, not for you personally — pricing it per visitor would mean calling eBay on every page view, which the API budget does not allow. Check the real cost on the listing before bidding.

6. What this is not