Rule #1 seems evident. This is probably because it IS evident. However it’s easy to find RCAs (root cause analysis) that violate this rule. Here is an example I’ve recently seen:
Our machine was not clean before we started the new batch. The operator that verified it did not see that one piece of the machine was dirty. He was new to the job and failed to follow the standard checklist properly. The root cause of our defect is “defective cleaning verification due to incomplete training”.
Yes, you got it. The “defective cleaning verification” cannot be the root cause because it happened AFTER the problem appeared. The machine was already dirty at that moment, which is the real problem. The adherence to the standards and the correct training of all operators are, of course, fundamental but it is not creating this issue.
Our quality systems are based in 3 types of actions: those that eliminate the problem, those that mitigate the effect of the problem and those make the problem visible. All of them are important, but only the first solve the root cause forever and improve the quality of our work. Without proper RCA, we will have the same issues again and again. This is why RCA is so important.
A few days ago I wanted an omelette for dinner. Sadly I found out that I did not have any eggs at home. I live downtown and I have a supermarket very close to my apartment, so I decided to go to the supermarket just to buy the eggs I needed. I took to me 2 minutes to get there, 5 minutes to buy them and 2 minutes again to come back home. Total Lead time = 9 minutes.
I was quite happy about the shopping experience. Why? Consider the benefits of having the supermarket so close:
- I can buy small portions of food anytime, so I don’t need big storage areas at home (= fewer inventory areas wasted in my apartment).
- I don’t need a big fridge to keep food fresh for long periods of time (= inventory areas are cheaper and power consumption is lower)
- I don’t need a car to get my food ( = cheaper transport, better for the environment)
- The weight of my shopping bag is low ( = this is great from a health & safety perspective)
- I don’t need to have big amounts of food at home, so I can keep my money in my pocket and not in my cupboard / fridge (= more cash is available).
- My shopping list is short, so it is very easy to write down and to remember all the items ( = no need of sophisticated scheduling systems, errors are easier to find)
- I can buy my food 30-45 minutes before I use it, so it’s ok if some friends come over unexpectedly (= emergencies and crisis are easier to handle)
- I can adapt easily to my own circumstances, like if I need special food because I’m sick ( = customer satisfaction is easier to get because the “moment when I buy the food” and the “moment when I eat the food” are close. No need of “special offers” to get rid of the food I’ve already bought but don’t need anymore)
It’s a good idea to keep the lead time controlled and to make it as low as possible. Reducing lead time improves all classic KPIs (Health, Quality, Delivery, Cost) and not just cost. Additionally, it gives you something extremely important but difficult to measure: flexibility. And flexibility can really make a big difference to your process.
This is the cathedral of Salamanca, Spain. It’s old and beautiful so it’s always full of visitors trying to get access to it, especially the gothic towers. The stairs that go up are narrow and long (it takes approx. 2 minutes to go to the top) and there is little room to move. In the past people tried to go up to the tower when other people were going down from the tower, so problems were frequent: people getting stuck and nervous, some panic attacks, long queues. The result: unhappy visitors.
Today there is a visual system that controls the flow of people. Surprisingly, this simple screen has made a big difference. Well, maybe it’s not such a big surprise: it is visually easy to understand, it combines color, graphs and text, and tells everybody in a very effective way if they are allowed to go or if they have to wait (and how long). Now the visitors know what to expect, no more hurries, no more frustration. Instead, there is a very good flow of people going up and down quietly and enjoying the visit. And best of all, people can organize themselves without any external help. Self management in place!
These are the wonderful views over the city from the top of the tower. It’s worth the wait!