The Goal: a process of Ongoing Improvement

accumulation
of the fluctuations. And mostly it’s an
accumulation of slowness
—because dependency limits the opportunities for
higher fluctuations. 
And that’s why the line is spreading. We can make the
line shrink only by having everyone in the back of the line move much faster
than Ron’s average over some distance.
Looking ahead, I can see that how much distance each of us has to make up
tends to be a matter of where we are in the line. Davey only has to make up
for his own slower than average fluctuations relative to Ron—that twenty feet
or so which is the gap in front of him. But for Herbie to keep the length of the
line from growing, he would have to make up for his own fluctuations plus
those of all the kids in front of him. And here I am at the end of the line. To
make the total length of the line contract, I have to move faster than average
for a distance equal to all the excess space between all the boys. I have to
make up for the accumulation of all their slowness.
Then I start to wonder what this could mean to me on the job. In the plant,
we’ve definitely got both dependent events and statistical fluctuations. And
here on the trail we’ve got both of them. What if I were to say that this troop
of boys is analogous to a manufacturing system . . . sort of a model. In fact,
the troop does produce a product; we produce "walk trail.’’ Ron begins
production by consuming the unwalked trail before him, which is the
equivalent of raw materials. So Ron processes the trail first by walking over
it, then Davey has to process it next, followed by the boy behind him, and so
on back to Herbie and the others and on to me.

---

Each of us is like an operation which has to be performed to produce a
product in the plant; each of us is one of a set of dependent events. Does it
matter what order we’re in? Well, somebody has to be first and somebody
else has to be last. So we have dependent events no matter if we switch the
order of the boys.
I’m the last operation. Only after I have walked the trail is the product
"sold,’’ so to speak. And that would have to be our throughput—not the rate
at which Ron walks the trail, but the rate at which I do.
What about the amount of trail between Ron and me? It has to be inventory.
Ron is consuming raw materials, so the trail the rest of us are walking is
inventory until it passes behind me.
And what is operational expense? It’s whatever lets us turn inventory into
throughput, which in our case would be the energy the boys need to walk. I
can’t really quantify that for the model, except that I know when I’m getting
tired.
If the distance between Ron and me is expanding, it can only mean that
inventory is increasing. Throughput is my rate of walking. Which is
influenced by the fluctuating rates of the others. Hmmm. So as the slower
than average fluctuations accumulate, they work their way back to me. Which
means I have to slow down. Which means that, relative to the growth of
inventory, throughput for the entire system goes down.
And operational expense? I’m not sure. For UniCo, whenever inventory goes
up, carrying costs on the inventory go up as well. Carrying costs are a part of
operational expense, so that measurement also must be going up. In terms of
the hike, operational expense is increasing any time we hurry to catch up,
because we expend more energy than we otherwise would.
Inventory is going up. Throughput is going down. And operational expense is
probably increasing.
Is that what’s happening in my plant?

---

Yes, I think it is.
Just then, I look up and see that I’m nearly running into the kid in front of
me.
Ah ha! Okay! Here’s proof I must have overlooked something in the analogy.
The line in front of me is contracting rather than expanding. Everything must
be averaging out after all. I’m going to lean to the side and see Ron walking
his average twomile-an-hour pace.
But Ron is not walking the average pace. He’s standing still at the edge of the
trail.
"How come we’re stopping?’’
He says, "Time for lunch, Mr. Rogo.’’

---

14
"But we’re not supposed to be having lunch here,’’ says one of the kids.
"We’re not supposed to eat until we’re farther down the trail, when we reach
the Rampage River.’’
"According to the schedule the troopmaster gave us, we’re supposed to
eat lunch at 12:00 noon,’’ says Ron.
"And it is now 12:00 noon,’’ Herbie says, pointing to his watch. "So we have
to eat lunch.’’
"But we’re supposed to be at Rampage River by now and we’re not.’’
"Who cares?’’ says Ron. "This is a great spot for lunch. Look around.’’
Ron has a point. The trail is taking us through a park, and it so happens that
we’re passing through a picnic area. There are tables, a water pump, garbage
cans, barbecue grills—all the necessities. (This is my kind of wilderness I’ll
have you know.)
"Okay,’’ I say. "Let’s just take a vote to see who wants to eat now. Anyone
who’s hungry, raise your hand.’’
Everyone raises his hand; it’s unanimous. We stop for lunch.
I sit down at one of the tables and ponder a few thoughts as I eat a sandwich.
What’s bothering me now is that, first of all, there is no real way I could
operate a manufacturing plant without having dependent events and statistical
fluctuations. I can’t get away from that combination. But there must be a way
to overcome the effects. I mean, obviously, we’d all go out of business if
inventory was always increasing, and throughput was always decreasing.

---

What if I had a balanced plant, the kind that Jonah was saying managers are
constantly trying to achieve, a plant with every resource exactly equal in
capacity to demand from the market? In fact, couldn’t that be the answer to
the problem? If I could get capacity perfectly balanced with demand,
wouldn’t my excess inventory go away? Wouldn’t my shortages of certain