Standards

We are regularly called on to report on the latency and packet loss to a remote location.  We allow the perl script to schlep the data into a csv file, which then gets exported into Excel to produce a graph.   Excel has great capability to create charts on-the-fly, edit, and annotate. But consider these two graphs, charting exactly the same data set:

 

 

The graph on the bottom produces a much dramatic display of latency, and washed out the packet loss.  The top graph emphasis the packet loss, while reducing the impact of the latency.  Both are accurate, but the tell a different story.

Typically, charts aren’t viewed in a vacuum, but are rather compared against other charts—charts of other locations, or historical charts.  For this reason, it’s important we compare charts of similar scale.

Not only must the axis be the same, but the proportions of the X and Y axis should be similar.

As part of the post-mortem templates, or performance report template, include graph standards: latency maximums, time-scales, and graph sizes.  It will make it easier for everyone to compare events as needed.