The 80-20 Rule of Analysis and Optimization

The Pareto Principle

The Pareto principle, also known as the 80-20 principle, says that 20% of the issues will cause you 80% of the headaches. This principle is also known as The Law of the Vital Few. In this post, I'll describe how the Pareto principle can guide your work to provide maximum benefit. I'll also describe a way to question the information at hand using a technique known as 5 Whys.

The 80-20 rule states that when you address the top 20% of your issues, you'll remove 80% of the pain. That is a bold statement. You need to judge its accuracy yourself, but I've found it to be uncannily accurate.

The implications of this principle can take a while to sink it. On the positive side, it means you can make a significant impact if you address the right problems. On the down side, if you randomly choose what issues to work on, it's quite likely you're working on a low-value problem.

Not quite enough time

When I first heard of the 80-20 rule I was bothered by another concern: What about the remaining problems? You should hold high standards and strive for a high-quality network, but maintaining the illusion of a perfect network is damaging. If you feel that you can address 100% of the issues, there's no real incentive to prioritize. I heard a great quote a few months back:

     "To achieve great things, two things are needed; a plan, and not quite enough time." - Leonard Bernstein

We all have too much to do, so why not focus our efforts on the issues that will produce the most value? This is where having Top-N reports from your management system is really helpful. Sometime you need to see the full list of issues, but only occasionally. More often, this restricted view of the top issues is a great way to get started on your Pareto analysis.

3G WAN and the 80-20 rule

A few years back, I was asked to design a solution for rapid deployment warehouses in remote locations. After an analysis of the options I ran a trial using a 3G-based WAN. We ran some controlled tests, cutting over traffic for 15 minutes, using some restrictive QoS policies. The first tests failed with a saturated downlink.

When I analyzed the top-talkers report for the site I saw something odd. It seemed that 80% of the traffic to the site was print traffic. It didn't make any sense to me, but the systems team verified that the shipping label printers use an 'inefficient' print driver.

At this point I could have ordered WAN optimizers to compress the files, but we did a 5 Whys analysis instead. Briefly, '5 Whys' is a problem solving technique that helps you identify the true root cause of issues.

• Why is the bandwidth so high? - Printer traffic taking 80% of bandwidth
• Why is printer traffic such a high percentage? - High volume of large transactions
• Why is the file size so large? - Don't know - oh yeah we use PostScript (or something)
  
• Why can't we use an alternative print format? - We can, let's do it, yay, it worked!
• Why do we need to ask 5 whys? - We don't, you can stop when you solve the problem

The best form of WAN optimization is to suppress or redirect the demand. We don't all have the luxury of a software engineer to modify their code and reduce bandwidth, but in this case it was the most elegant solution. We were able to combine a trial, reporting, top-N and deep analysis with a flexible team. The result was a valuable trial and a great result.

Summary

Here's a quick summary of what I covered in this post:

• The 80/20 principle can help you get real value from your efforts.
• Top-N reports are a great starting point to help you find that top 20%.
• The 5 Whys principle can help you dig deeper into your data and choose the most effective actions.

Of course a single example doesn't prove the rule.  Does this principle ring true for you, or perhaps you think it is nonsense? Let me know in the comments.