Improve your Lean with some Six Sigma (and vice versa)

With the advent in recent times of a combined lean and six sigma approach to continuous improvement efforts, one might think that the dilemma of which methods to chose has been resolved. However, confusion still exists over how to move forward with a combined approach to Lean and Six Sigma.

First, why a combined approach to Lean and Six Sigma? Isn't lean or six sigma good enough on its own? Not in all cases by my experience. Every problem is like a snowflake, unique, with some similarities to other problems but still, unique. For some types of problems six sigma is good enough all on its own, those types of problems are typically variation related issues. For other types of problems, lean is fine, those are typically waste related issues. Combining them together leaves nothing on the table in terms of improvement opportunities. Lean and Six Sigma each complement weaknesses in the other method. For instance, Lean is weak in the area of data based analysis and decision making, this is a strength of Six Sigma. Six Sigma is a top down driven improvement approach, which risks not involving the right people in solving the problem, lean compliments this by being driven bottoms up, ensuring the process users are involved in the improvement.

Add some lean to your six sigma or six sigma to your lean. In studying both Lean and Six sigma, we find that they operate on multiple levels. Lean and Six Sigma are at once, a tool set, a methodology, and a culture. Much handwringing has occurred over the question of creating another initiative when a six sigma or lean culture already exists. Concerns usually center on creating confusion in the ranks. Avoid this confusion by folding the supporting tools and method into your existing improvement culture. If six sigma is your way of working, incorporate lean tools into the method to capture waste in addition to the variation reduction. If you have a Lean culture, add the six sigma data gathering and analysis tools and steps to your lean to strengthen your decision making.

I  led a couple of projects that are good examples demonstrating the idea of combining approaches to achieve the best results. Without going into much detail on them I can share that in the first project we improved process accuracy by over 40% while reducing cycle time from 45 to 19 days.This project can be reviewed here for those interested in more detail. In the other project we reduced cycle time by 40 hours through using regression statistics to identify what equipment was producing the longest cycle times, then apply lean concepts to improve them.

The point here is that combining lean and six sigma approaches together improves results by reducing variation and reducing waste at the same time. This is the best use of our precious improvement resources, gaining the maximum benefit for the time and effort spent focused on a particular problem.