The Lean Anthology

119

Chapter 11

Designing Experiments

BOB’S A- MAIZE- ING POPCORN

Bob: Hi, Jay. Thanks for making it over.

Jay: Glad to be here. Who else is here

already? The game should be

starting soon.

Bob: Mike and Dave are in the den,

watching the pregame show

and finalizing their fantasy

teams. I think we’ve got about

15 minutes before kickoff.

Jay: Sounds good. Hey, what’s that

smell? Is something burning?

Bob [runs to the kitchen]: Whoops! I

thought the guys were watch-

ing the stuff they brought. [Frantically pulls on some oven mitts

and slides out a tray of burned mozzarella sticks and chicken

wings.] Open the window!

Jay [pops open a window and fiddles with the remote control for the ceiling

fan]: That’s a lot of smoke.

Bob Leibe describes his son’s science

fair project—popping the perfect

corn—to his friend, Jay, who has come

over to watch a football game. He

describes their process for identifying

variables, as well as their objectives and

definition of success. Last, he discusses

the results of their research, which

include insight into which variables

have the greatest effect on the outcome.

As you read Bob’s story, think

about what he and his son might do

next to continue the popcorn improve-

ment process.

120 THE LEAN ANTHOLOGY

Bob: Give me that. [Reaches for the remote control and puts the fan on high

speed.] Well, what are we going to eat now? Beer alone isn’t

enough. I’ve got to eat something, or my ulcer will act up.

Jay: I don’t think anyone’s going to want to go to the store again. What

do you have in the house? Can we make some popcorn or

something?

Bob: Good idea. [Closes the window now that the smoke has cleared.] I

make the best popcorn this side of the Mississippi.

Jay: How could you possibly know that your popcorn is the best?

Bob: Because Malachi and I have popped a batch every day for the

past month as part of his science project. For some reason, I

haven’t gotten tired of eating our research.

DESIGNING EXPERIMENTS 121

Jay: What’s the science project about? I’ve got to do something similar

with Vicky next month, and I could use some ideas.

Bob [gets his popcorn equipment out and opens a cabinet to reveal 12 bags of

popcorn from different manufacturers]: We designed the project

to demonstrate how to control several variables in a process

to standardize and optimize the outcome.

Jay: What does Sandy have to say about all this?

Bob: She loves it. We always clean up the kitchen after conducting our

top- secret activities. I usually cooked dinner anyway before

we started this project because she worked late, and then she

did the dishes—now it’s easier for her because she gets din-

ner and a clean kitchen.

Jay: You’re a real treasure!

Bob: Yeah, tell me about it. Anyway, we started the project by taking a

look at the variables that we guessed would have the great-

est effect on the outcome. We first looked at six variables,

and we went back and forth about which ones were the most

important. We wanted to design the project in the way we

thought it would be most effective. When we first started

talking about it, we looked at the brand of kernel, the thick-

ness and density of the pan bottom, lid seal tightness, pop-

ping medium (oil or air), gas or electric stove, and toppings.

Jay: How would you even know where to start? That’s not a very spe-

cific list. You could test those things forever and not come up

with anything definitive. Don’t science experiments isolate

one or two things, so the outcome is more controlled?

Bob: Yes, that’s true, but Malachi enjoys debating the minutiae, so we

delved quite deeply into the details of those six things on our

initial list. First of all, we have an electric stove, not a gas

range. So we thought about that. We realized that our gas-

versus- electric line item was more a matter of the ability to

control temperature. For the purposes of this experiment, we

realized that we could simply preheat an electric stove burner

so that the popcorn pan was introduced to high heat fairly

quickly, the same way as a gas stove. We also lowered the

heat inside the popcorn pan by moving it to another burner

that was not currently in use to duplicate the superior tem-

perature control of a gas stove. Therefore, for the purposes

of this experiment, we removed that variable from the list.