I would like to set an alert based only negative percentage occurrences in traffic pages. I believe any positive percentage change is good because we are talking about the traffic, but I am more interested to set an alert in negative percentage changes to monitor any misbehavior of the site and not only the complete blackout from the server. For Example if you set an alert by percentage changes like 50% then you will received an email either +50% and -50% and I would really like to avoid positive changes over-flood emails.
After I submitted an question the ClientCare responded "Negative percentages are extremely rare. If you would still want to setup an Alert letting you know when a negative percentage occurs you can setup the Alert to show: " is below 0" for this report."
The above instruction from ClientCare did not work as I expected. I think negative percentage occurance would be a great tool for monitor purposes.