What is invalid traffic in search arbitrage?
Invalid traffic is any visit or ad click that should not be charged to an advertiser: bots, repeated or automated clicks, people paid or tricked into clicking, and clicks made by accident. In search arbitrage it matters twice over, because the publisher has already paid for the visitor and will not be paid for the click.
Not all invalid traffic is fraud. A monitoring crawler is invalid but innocent. A reader whose thumb hits an ad while scrolling made an accidental click. Fraud is the deliberate part: Bot traffic, a click farm, incentivised traffic.
For an arbitrage operator the question is where it enters. Most arrives with bought traffic: low-quality placements on native networks, resold inventory, or sources that mix in non-human visits. Some is caused by the page itself through layouts that provoke mistaken clicks. Either way the search engine filters it and the cost lands on the publisher as a clawback or lower RPC. Measuring it per source with IVT detection turns an invisible cost into a decision.