Campaign Tracking is not 100% accurate, but it is very close when it is set up right. Here are some reasons for discrepancies and some things you can do to make sure the numbers match up:

• The search engine can only report what happens on their site, we can only report what happens on your site. If your site is down, or people click thru and then close the browser before arriving at your site, the search engine will still count it as a click thru even though they never really did hit your site.
• Google Network: Google displays ads on sites other than Google. They will charge you for this even though your customers aren't coming from Google.
• Time discrepancies: We report our statistics on whatever time zone you want. Not all search engines do this. Google reports all statistics on US Pacific Standard Time. If you want to track according to Google, you need to change your time to US Pacific Standard Time.
• IP selection: Your may have chosen to filter out your own visits. AdWords will still count your own visits. To match exactly with AdWords, you must stop filtering your IP address.
• Stolen links: Your link may have been stolen by someone else. Every time they click on the link, it will report as a paid per click, even though it is being used by someone else. If this is a problem, you may consider redoing your links.