Complete Web Monitoring

Aggregation and Visualization

We’ve seen several examples of how synthetic tests report data. Let’s look at a few other common representations of end user experience. One way of reporting performance is to segment it by region or carrier to identify the worst-served parts of the Internet, as shown in Figure 9-28.

Figure 9-28. Webmetrics transaction performance report by geographic region for a site on the East Coast of North America

Segmented reports show you the slowest or least-available tests along a particular dimension. But what if you want to focus on a particular element of latency? Synthetic tests collect a great deal of data, and you need to look across all of it to properly understand what normal performance is like.

By displaying a metric—such as total transaction time—as a histogram, you can quickly see what kind of performance is most typical. On the other hand, you may not want to aggregate data, but rather see individual tests to better understand a particular period of time. In this case, a scatterplot visualization like the one shown in Figure 9-29 works well.

Figure 9-29. A scatterplot of individual test results

This kind of report is only available from services that keep the raw test data for considerable lengths of time. Some lower-cost services will aggregate this information ...