How LeakStop measures waste
Last updated: August 17, 2026 · The working standard: every number shown to a user is either derived from that user's own data, or labelled an estimate with its method named.
Recoverable
Spend on search terms with at least 5 clicks and 0 conversions that also share a theme with other non-converting terms, where that theme never appears in a converting search. That is precisely the waste a negative keyword removes without collateral damage, which is what the word has to mean if the figure is going to survive a sceptical reader.
It is measured from the export, never taken as a percentage of it. Waste that occurs once is reported separately as unclustered, because no negative keyword removes a search that happens once, and counting it would inflate the headline with money the reader cannot get back.
Summed per term, never per n-gram. A search sits under several themes at once, and adding up the themes would count the same pound twice and report more recoverable waste than the account spent.
Safe to negative
Every theme carries its converting side as well as its wasted side. A theme that also appears in searches that earned is shown, and never suggested — recommending "free" as a negative while "free consultation" converts is not a wrong estimate, it is advice that costs the reader money.
Where a theme is unsafe but the money is real, the account's own conversions choose the match type rather than whether to report: the suggestion falls back to exact negatives on that cluster's own zero-conversion terms.
Well evidenced
A query performing at exactly the account's own conversion rate still shows zero conversions with probability (1 − rate)^clicks. At a 6.1% account rate that is 64% of the time on seven clicks. So spend counts as well evidenced only once it has enough clicks for a run of zeros to be unlikely at that account's rate: ceil(log 0.05 / log(1 − rate)) — 48 clicks at 6.1%, 116 at 2.55%, 8 at 33%.
This labels strength; it is deliberately not a filter. Measured across our validation corpus, gating on it would delete four of the five findings the product makes, including the one with independent human confirmation — an account whose own analysts hand-excluded the same query family we flag. Their judgement was semantic, not statistical, and a bar that overrules it is quieter, not truer.
What you could have found by sorting
Reported on every audit. We take the terms making up the recoverable estimate and rank them against every zero-conversion row by cost — your view, taken with no click floor and no theme test, so the comparison is deliberately generous to it. Where most of our estimate sits in the rows you were going to read anyway, the report says so instead of selling you something.
On one real account of $342,047 across 54,112 search terms: recoverable $8,285, of which 12% sits in the twenty most expensive zero-conversion rows. Reaching 80% of it means reading 2,773 rows. The median flagged row cost $12; row twenty of the sorted list cost $166.
When we decline to judge
If an export records no conversions anywhere, no waste rule speaks. Waste is spend that produced nothing while other spend produced something, and an export with no second half has no comparison to make. Above 100 clicks the report additionally says the likely cause is tracking rather than waste; below it, a quiet month is not evidence of anything. This is why an account can upload real spend and correctly receive no estimate.
Thresholds, and which of them are calibrated
Money floors are expressed as shares of the account's own 30-day spend, never as absolute amounts. An absolute figure carries no currency: a "$500/month" floor is about $3 for a Japanese advertiser, and would fire on everything. Ratios are scale-invariant — which is not the same as calibrated, and we say so.
The savings ledger's baseline is the one constant that has been measured against outcomes: across 2,251 days from three real accounts, each 28-day baseline compared to the 90 days that actually followed came out at a median of 0.84–0.99 and a 90th percentile of 1.07–1.20. Conservatism holds at the middle. The tail is seasonality, which the outlier clipping structurally cannot reach, and a leak sealed just after a seasonal peak can accrue against a baseline well above what that scope went on to spend. That is a limitation, not a footnote.
What we do not claim
- That the estimate is money you will recover. It is the spend a negative keyword could remove without cutting traffic that earns. Acting on it is your decision and your judgement.
- That silence means a clean account. It usually means the rules found nothing they can stand behind on the data you gave them.
- That our figures replace your own. Everything above is computed from the export you upload, and every input to it is a column you can read yourself.