I think we all know what the Law of Diminishing Returns is but for the sake of clarity I’ve included the wise words of Wikipedia to improve our understanding.
Definition from Wikipedia:
“According to this relationship, in a production system with fixed and variable inputs (say factory size and labor), beyond some point, each additional unit of variable input yields less and less additional output.”
Example from Wikipedia:
“Suppose that one kilogram (kg) of seed applied to a plot of land of a fixed size produces one ton of harvestable crop. You might expect that an additional kilogram of seed would produce an additional ton of output. However, if there are diminishing marginal returns, that additional kilogram will produce less than one additional ton of harvestable crop (on the same land, during the same growing season, and with nothing else but the amount of seeds planted changing). For example, the second kilogram of seed may only produce a half ton of extra output. Diminishing marginal returns also implies that a third kilogram of seed will produce an additional crop that is even less than a half ton of additional output. Assume that it is one quarter of a ton.”
So to create an analogy from the example above let us assume that each ton of seed is equivalent to 30 minutes of training and the plot of land is our brain. It is easy to speculate that if 30 minutes of training on a task leads to a 10% increase in knowledge then 60 minutes of training on a task will lead to a 20% increase in knowledge in the same training session. If no other variables change beyond the length of the training session, it is probably more likely that there will only be a 15% total increase in knowledge. If you increase the training session length by an additional 30 minutes you may only increase the total knowledge transfer to 17% and so on.
Before somebody quotes me as saying that you can only get a 17% increase in knowledge in 90 minutes, it is important to remember that we are just building from the original Wikipedia example in order to clarify a key principle. That principle is that training follows the Law of Diminishing Returns.
Now I will proceed to use some anecdotal data to further prove my unscientific point. Have you ever sat through an 8-10 hour training session on a single topic in a single day? If the answer is yes, then you already know this is true because at the end of the day you may actually feel dumber (not sure this is a scientific word or not) then when you started. This is an example of planting so many seeds that you actually poison the ground so that it can no longer produce.
Today I spent about 90 minutes in a class on Chinese. During that time we learned how to pronounce several pinyin syllables and say a few useful phrases. By the 89th minute the only thing I could remember was how to pronounce the vowel “i” in pinyin.
Maybe our brains are like water balloons and every once in a while we just put in too much water and end up springing a leak at the nozzle.
I was listening to a podcast from our friend Mark Graban over at the Lean Blog where David Meier mentioned that we generally want to chunk the training into about 30 minute blocks. 15 minutes of that might be presenting and explaining the task and the other 15 minutes the learner would be demonstrating that they can explain and perform the task.
Now that is more like it. I can’t even start daydreaming in 15 minutes. And the second 15 minutes is all about me showing that I learned something. That sounds like training heaven. In training Hell they make you sit through a 90 minute lecture followed by a 5 minute bio break and 90 more minutes of lecture.
To simplify your comments on this blog I’m adding a multiple choice question:
What is your training threshold?
a) < 1 minute
b) 1-15 minutes
c) 15-30 minutes
d) >30 minutes
e) The average training hell is my training heaven
Mike Gardner says
My threshold is a lot longer than a few minutes, but that is a product of my background and eduation, I think.
Your post additionally illustrates a problem in manufacturing and business training in general–a task-oriented mindset. You discuss half-hour blocks wherein a person is trained to perform a task. That’s fine, but that does not speak to the ongoing education of an employee. Knowledge is not all task-oriented. To develop truly empowered and engaged employees requires education based on a long-term view of their potential as a member of the organization and not simply “training” them to perform multiple routine tasks. There is a need for that kind of training, but it is all most employees usually receive. It is unfortunate that lean thinkers spend so much time developing improved methods to teach people to do various routine tasks (TWI for example) instead of educating them to develop their full potential to contribute to the business or organization in ways not even imagined yet.
Craig Woll says
Thanks Mike! I always appreciate a great comment that allows clarification. I completely agree with your synopsis of education. I am an educator by profession and a lean enthusiast by choice. Yet I still believe that chunking, sequencing, and timing are important in planned learning events even in non-task oriented learning. I simply used a task based approach to explain this concept as it simplifies it some.
About 80% of learning probably occurs through experience in life or by doing something with what was passed along through formal channels. When viewing long-term potential it seems that we would want to maximize what they can learn by giving them an opportunity to solidify the learning from the formal environment through the application. Therefore, by giving a chunk of information followed by a bunch of application and accompanied with some strong mentoring you can get dramatic long-term results. This develops more then just a skill since a good mentor can focus on business acumen, communication, problem solving, leadership, and other important topics that are difficult to teach in the formal environment.