I agree with many of the points in the article, however it is conflating two unrelated things. Using simple averages in isolation is almost always a mistake.

I agree with many of the points in the article, however it is conflating two unrelated things. Using simple averages in isolation is almost always a mistake. The real story in a system almost always lies in it's variation and not in the average. There are many ways to look at that, one of them is a histogram, although I tend to prefer time series graphs with moving ranges. One of my favorites is the Xmr chart or any of a number of statistical process control charts. Using those you can get a much better understanding of systems over time. The transition to Real User metrics is not at all related to using an average. All recording and instrumentation processes will benefit through using more sophisticated and nuanced tools than a simple average. Real user metrics are an important data point, but they lack certain information you can get from external monitoring systems. We use both pingdom and catchpoint, by far my favorite is Catchpoint because I can see things like what ISP is involved with a slow request, what geographic region, etc. I can also get scatter plots and nice statistical graphs around median, geometric mean, 75th, 95th, 99th percentile. So in short the main points are good, simple averages are misleading. Capturing end user performance data is good. Not using external monitoring though isn't a good idea because there a number of things that you can identify if you have that insight.