We've posted a new blog post at TNG and invite you to take a look. Not only are we big on performance bench marking, but ways of making bench marking actionable are also important. In this blog post we talk about standard deviation and how that can be an important way to make bench marking more relevant for your business.
Here is an excerpt:
"One hard part about performance monitoring is knowing when performance is unusual—either good or bad. If you have 50,000 visitors to your website in March, is that normal? You might rightfully ask what the benchmark is. What if the benchmark is 40,000 visitors a month? Then a number like 50,000 looks pretty good. That's 25% growth in one month! However, even comparing to the benchmark could be misleading because we are not taking variability into account...
When doing performance benchmarking, standard deviation is a good way to balance the highs and lows against the average and come up with a "normal" range. When we apply standard deviation to website traffic, we are looking for spikes and dips that fall outside the normal range. When you find these exceptional data points, you can make recommendations to investigate what was going on."