The first thing every new CallerSift customer does is stare at their block rate. The second thing they do is ask whether it is good or bad.
Wrong question. Block rate is not a grade, it is a report card for your traffic sources, and it only becomes useful when you stop reading it as one number.
The number by itself means very little
A campaign-wide block rate of 12 percent tells you almost nothing on its own. It could mean one poisoned affiliate buried in nine clean ones. It could mean incentivized traffic doing what incentivized traffic does. It could mean your geo targeting is pulling from a market where burner-app usage runs hot.
Averages hide the story. The distribution is the story.
Segment first, always
Split your lookups by traffic source and the flat number turns into a diagnosis:
- One source high, the rest low. The classic. An affiliate is padding volume with manufactured calls. You do not have a fraud problem, you have a partner problem, and now you have the receipts for that conversation.
- Everything uniformly elevated. Look at the campaign itself. Duration-based payouts, aggressive incentives, or promo placement on low-quality inventory all invite junk across every source at once.
- A sudden spike on a stable source. Something changed upstream: the affiliate bought new inventory, a promo code leaked to a deal forum, or someone found your campaign and pointed a dialer at it. The timestamp of the spike usually tells you which.
The lookups view in CallerSift carries source, verdict, reason, and time for every screened call, and exports to CSV or Excel when you want to slice it your own way.
A zero block rate is also a finding
New customers sometimes celebrate a week of 0 percent blocks. Occasionally that means pristine traffic. More often it means the lookup URL is only wired into one leg of the campaign, or the tracker is only pinging on calls that already passed some other filter. Verify the plumbing before you frame the trophy: total lookups in your dashboard should match total inbound calls in your tracker, call for call.
What a healthy account looks like
Across pay-per-call generally, clean consumer campaigns tend to settle into a low single-digit block rate, mostly VoIP stragglers and the odd recycled number. Numbers meaningfully above that are usually concentrated in a source or a placement, which is exactly what the segmentation is for. There is no universal threshold, and anyone who sells you one is selling you a dashboard ornament.
The useful discipline is watching movement, not level. A source that drifts from 3 percent to 8 percent over two weeks is telling you its inventory mix changed. Ask about it while the drift is small.
Turn the number into policy
Block rate earns its place on your screen when it changes what you do:
- Set a review threshold per source. When a source crosses it, the calls get sampled and the partner gets a question, not an accusation.
- Tie renewals to the trend. Sources that stay clean earn budget. Sources that need weekly conversations do not.
- Feed it back into buying. The cheapest fraud is the campaign you never fund again.
Screening blocks the bad call in the moment. Reading the block rate keeps next month's traffic from needing so much screening. The dashboard does both from the same table.