Piwik shows fewer campaign visits compared to number of clicks tracked by pay per click site

Hi, I did read over through the FAQ and search previous forum topics to look for answers; however, my question is somewhat general and may only be answered with some general suggestions or recommendations anyway.

Unfortunately, I cannot reveal lots of detail about this, but we pay for advertisements (cost per click) from a third party site. So far, this third party site has tracked a little more than 2,500 clicks - while Piwik shows around 1,500 visits coming through that campaign (same period of time).

Does anyone have general info that might explain why there is such a big difference? (We are on version 1.6, and the campaigns have been tagged properly and verified to be working.)

Some initial possible explanations I am considering:

  • visitors with javascript disabled
  • possible accidental double-clicks ( “multi-click” ) on the advertisement link?
  • could it be search engine bots that are following the advertisement link, but they get excluded (by design) by Piwik’s javascript?

If anybody has any more helpful information that might explain the difference, I would appreciate it. Thank you

Your suggestions are indeed the most likely reasons for discrepancies…