Case study: a VoIP filter trade-off — 13% fewer leads, 21% more FTD

Case study: a VoIP filter trade-off — 13% fewer leads, 21% more FTD

What it is: A careful test of whether blocking VoIP-flagged phone numbers actually improves forex lead quality, or just shrinks volume for no gain.

Best for: Teams already running line-type lookups who debate hard-blocking VoIP.

What was done:
— Ran 7,100 leads with VoIP numbers passed through (control) vs blocked (test)
— Used a number-intelligence API to classify line type at submit
— Tracked downstream FTD on each group

Outcome:
— Blocking VoIP cut lead volume 13%
— But FTD rate on remaining leads rose 21% (VoIP leads converted at a third the rate)
— Cost-per-FTD fell 18% despite paying for the classification step

Pros:
— The data settled an argument with numbers instead of opinions
— Connect rates improved because VoIP numbers were often unreachable

Cons:
— Legitimate users on Google Voice / business VoIP got blocked too
— Line-type databases disagree; a slice was misclassified

Who should skip this: Geos where VoIP is the mainstream consumer line type — you'd block real users.

Verdict: Block VoIP, weigh the loss.