Measuring Forecast Accuracy

Supply Chain Forecast Accuracy is usually measured with Mean Absolute Percent Error or MAPE, the average of percentage errors. But there are several other metrics to consider. Here’s an example …

Lean Six Sigma Certification Game

A friend and colleague, Bill Bentley, writes about the use of professional certifications in the recruiting industry. I had a long talk with a senior IT professional in Chicago last week expressing his deep frustration that despite his long and distinguished professional career, he could not get interviews without certain certifications despite being able to […]

Forget the 80/20 Rule

In the late 1800s, economist and avid gardener Vilfredo Pareto established that 80% of the land in Italy was owned by 20% of the population. While gardening he later observed that 20% of the pea pods in his garden yielded 80% of the peas that were harvested. And thus was born a theory that has […]

EVOP – Evolutionary Operations

  Evolutionary Operations, first described by George E. P. Box and Norman R. Draper in in their book Evolutionary Operations – A statistical method for process improvement, New York: John Wiley and Sons, 1969. EVOP is Continuous Improvement + Design of Experiments. Basic idea is to replace the routine  operation of a process by continuous […]

Fixed Repeating Schedule – Product Family Turnover Rate

Here’s another example for “sizing the wheel” for a mixed model fixed repeating schedule. Given: Changeover Time = 100 minutes Available Production Time = 2 shifts * 7 hrs/shift * 60 min/hr = 840 min/day and Product Daily Demand (pcs) Cycle Time (min.) Load (min.) A 80 5 400 B 40 4 160 C 20 […]

Process Improvement in a Down Economy

Many business leaders fail to see the opportunities that an economic downturn provides.  To take advantage of opportunities you first need to make a rapid assessment of your vulnerabilities and then move quickly to minimize them.  Advantage can be gained by using process improvement tools to increase profitability and competitiveness: Drive out waste through Lean […]


  Johann Carl Friedrich Gauss (1777-1855)  seen here on a German 10 Deutsche Mark banknote was a mathematician, astronomer, scientist noted for least squares, the normal distribution, and number theory.  Also known as the Gaussian distribution, the normal distribution is defined by the mean ("average", μ) and variance (standard deviation squared, σ2). The standard normal […]

5 Rules of On-error Training

  1. Ownership Rule – the person who first detects the problem is responsible for finding the root cause of the problem. 2. Quickly Rule – the problem must be dealt with and solved within 30 minutes, not put on a list or in a report for action at another time. 3. Actually Rule – […]

PowerPoint and other miscommunications

Recently read Edward R. Tufte’s The Cognitive Style of PowerPoint: Pitching Out Corrupts Within and initially dismissed his thesis as troglodyte.  Now sensitized, I’ve been watching for evidence of PowerPoint Abuse.  Found an unfortunate example with two parallel teams during a strategic capital equipment review.  Both teams were given the same mission and access to […]