Current score: 20.0 (only servers with a score higher than 10 are used in the pool)
Green/orange/red small dots are offsets (in milliseconds, using the left axis).
Blue/red "double size" dots are points/scores (using the right axis).
The y-axes (both) aren't linear to highlight what is usually the most interesting area of the data.
The Score graph
A couple of times an hour the pool system checks the time from your server and compares it to the local time. Points are deducted if the server can't be reached or if the time offset is more than 100ms (as measured relatively crudely from the monitoring systems). More points are deducted the bigger the offset is.
It's only meant as a tool to visualize trends. For more exact details of what the monitoring system found you can click on the CSV link.
The Offset graph
The monitoring system works roughly like an SNTP (RFC 2030) client, so it is more susceptible by random network latencies between the server and the monitoring system than a regular ntpd client would be. In other words: Don't be alarmed by the occasional large offset and please don't use the offset as an absolute performance metric.