Chartbeat alerts you when your Site receives unusually low traffic (concurrents) via Internal, Links, Search, or Social traffic sources. Low traffic threshold is calculated based on Site's historical data during that period of the day, this threshold is automatically calculated by our proprietary algorithm. A drop alert does not necessarily mean your Site or implementation is having an issue - it may indicate that a certain referral source is driving less traffic than usual to your Site.
Our default threshold is calculated as a Site's average traffic minus 3 times standard deviation per traffic source. However our algorithm will automatically lower this threshold to avoid random spikes leading to overalerting.