I have noticed a sharp decline in ROI (ie Actual Income vs adwords cost) from 70% to 41%
I wonder if someone is clicking on the ads just to eat up my budget!
How can I find whether this is happening?
There is a system in place to detect invalid clicks on AdWords accounts, all clicks on AdWords ads are examined by Google to seek out suspicious click activity, and Google do take this very seriously. Invalid clicks are then either filtered from your account or you will see "adjustment - click credit" listed in your billing if you were previously charged for clicks that were determined by Google to be invalid. PLease see "Invalid clicks" for more informationa bout this. Also for further understanding of how the process works, "How Google detects invalid click issues".
This article "what can I do to monitor or prevent invalid clicks" gives good advice about how to track, monitor and optimise against invalid click issues. You can also try using the invalid clicks trouble shooter, and finally you can also report suspicious activity should you find it necessary, but Google urge you to carry out your own account monitoring and optimisation first. Please see "click volume and invalid clicks" for further informationa bout this subject, and for information about reporting invalid clicks, please see "Reporting invalid clicks to Google"
Good luck with this, I hope you get it resolved :-)
Ooops forgot to mention also, you can add a column to your campaigns statistics to see invalid clicks that have been picked up and automatically filtered from your account. Click on your campaigns tab and click columns > customise columns. You can add invalid clicks to your table from there and click to save :-)