What is invalid traffic in advertising?
Invalid traffic (IVT) is any ad impression, click or visit that was not generated by a real person with a genuine chance of seeing the ad. It includes harmless automation such as search-engine crawlers as well as deliberate fraud like bots, hidden ads and spoofed websites. Advertisers should not pay for it, so the industry filters and measures it.
The term comes from the Media Rating Council, whose MRC IVT guidelines split invalid traffic into two buckets: GIVT (general invalid traffic, the easy-to-spot kind such as known crawlers and data center traffic) and SIVT (sophisticated invalid traffic, which tries to look human). Not all IVT is fraud: a price-comparison crawler or a monitoring tool is invalid but not malicious. Ad fraud is the subset where someone is deliberately faking activity to get paid.
IVT matters because most digital ads are bought per impression (CPM) or per click (CPC). Every fake impression is money that did not reach a human, and it also pollutes the data advertisers use to optimize. That is why buyers use pre-bid filtering to avoid suspicious inventory and post-bid measurement to report the IVT rate after the fact.