In the previous post, I introduced the work loop1.
Anyone familiar with systems dynamics will recognize the stocks and flows in this diagram. A stock is something that can increase or decrease over time. Work to Do, for example, is a stock that will decrease as work gets done and will increase as new or rework is added back into the stock. Flows are the rate at which each of these possible events change. With a high rate of progress and a low rate of error generation, the amount of Work to Do rapidly decreases while the amount of Work Done rapidly increases.
However, if the rate of error generation is high than the amount of Undiscovered Rework will increase at a faster rate. If rate of discovery for rework is high (as would be the case with a skilled and capable quality assurance team) than the amount of Rework to Do also increases rapidly which in turn feeds into an increase of the amount of Work to Do.
That’s the narrative version of the diagram in Figure 1.
There is another feature to reading system diagrams that will be important to understand as it will be key to understanding the dynamic quality of the model we’ll be building in subsequent posts. That feature is the interactions between the various elements and the effects of that interaction on stocks and flows. It is typically represented by a solid black arrow.
“A” has an interaction with “B” and that interaction is in the direction of “A” to “B.” But what’s the effect of “A’s” interaction with “B?” To display this effect, a green open head arrow or a red closed head arrow is used to describe the type of interaction between the two elements.
A green open-head arrow (Figure 3) is a direct relationship. A red closed-head arrow (Figure 4) is an inverse relationship.
To help understand these relationships, consider the analogy of being in the driver’s seat of a car. Imagine the car has a constant speed of 40 miles per hour. The car has been designed to go this speed with your feet off the peddles. (Not a particularly useful design feature, I’ll grant. But this is a thought experiment. So ride along with me for a little while.) Now, when you increase (↑) pressure on the gas peddle the car’s speed increases (↑). If you decrease (↓) pressure on the gas peddle the car’s speed decreases (↓) . If you remove all pressure on the gas peddle, the car returns to the constant 40 mile per hour speed. That’s the direct relationship illustrated between “A” and “B” in Figure 3. As “A” increases, so does “B.” As “A” decreases, so does “B.”
Now for the brake. If you increase (↑) pressure on the brake peddle the car’s speed decreases (↓) – it slows down to something less than 40 miles per hour. Increase the pressure on the brake enough and the car will stop. However, if you decrease (↓) pressure on the brake the car’s speed begins to increase (↑). If you remove all pressure on the brake peddle, the car returns to the constant 40 mile per hour speed. That’s the inverse relationship illustrated between “A” and “B” in Figure 4. As “A” increases, “B” goes the opposite way and decreases. As “A” decreases, “B” goes the opposite way and increases.
Back to Figure 3 – more of “A” results in more of “B” (↑↑) while less of “A” results in less of “B.” (↓↓) In Figure 4 – more of “A” results in of less of “B” (↑↓) while less of “A” results in more of “B.” (↓↑)
That’s all the system dynamics you’ll need to understand the subsequent posts that begin to build out the model. The power of the model is in understanding all the various interactions and recognizing the patterns within an organization or on a team that reveal the effects of those interactions. In the next post in the series we’ll see how a few soon-to-be-named elements interact with the work loop.
Before you go, however, read through the following phrases and make a mental note of those that resonate with you – either because you have heard them before or perhaps because you have uttered them yourself while working on a project.
- “We’re not moving the delivery date.”
- “We’ll just have to work harder.”
- “The team will have to put in more time until we’re caught up.”
- “We’ll need more people on the project.”
- “The team will have to work faster.”
- “We’re to the point of exhaustion.”
- “I’m losing track of all the pieces.”
- “There’s no time for training.”
- “Where did those errors come from?”
- “We’re waiting on another team.”
- “Another person quit the company?!?!”
- “I don’t care. I get done what I get done when I get it done.”
Previous article in the series: Assessing and Tracking Team Performance – Part 2: Work, Work, Work…
Next article in the the series: Assessing and Tracking Team Performance – Part 4: Let the Interactions Begin!
1The core of the model I use to assess team and organization health is based on the work of James Lyneis and David Ford: System Dynamics Applied to Project Management, System Dynamics Review Volume 23 Number 2/3 Summer/Fall 2007