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The Goal: A Process of Ongoing Improvement, Third Revised Edition

Page 16

by Eliyahu M. Goldratt


  "No, no, no, no," I say. "The game does not work that way.

  You can only pass the matches that are in your bowl."

  "But I've only got two," says Ben.

  "Then you can only pass two."

  "Oh," says Ben.

  And he passes his two matches to Chuck. I record a deviation

  of-1.5 for him too.

  Chuck rolls next. He gets a five. But, again, there are only

  two matches he can move.

  "Hey, this isn't fair!" says Chuck.

  "Sure it is," I tell him. "The name of the game is to move matches. If both Andy and Ben had rolled five's, you'd have five

  matches to pass. But they didn't. So you don't." Chuck gives a

  dirty look to Andy.

  "Next time, roll a bigger number," Chuck says.

  "Hey, what could I do!" says Andy.

  "Don't worry," Ben says confidently. "We'll catch up."

  Chuck passes his measly two matches down to Dave, and I

  record a deviation of-1.5 for Chuck as well. We watch as Dave

  rolls the die. His roll is only a one. So he passes one match down

  to Evan. Then Evan also rolls a one. He takes the one match out

  of his bowl and puts it on the end of the table. For both Dave and

  Evan, I write a deviation of-2.5.

  "Okay, let's see if we can do better next time," I say.

  E.M. Goldratt

  The Goal: A Process of Ongoing Improvement

  Captured by Plamen T.

  114

  Andy shakes the die in his hand for what seems like an hour.

  Everyone is yelling at him to roll. The die goes spinning onto the

  table. We all look. It's a six.

  "All right!"

  "Way to go, Andy!"

  He takes six match sticks out of the box and hands them to

  Ben. I record a gain of+2.5 for him, which puts his score at 1.0

  on the grid.

  Ben takes the die and he too rolls a six. More cheers. He

  passes all six matches to Chuck. I record the same score for Ben

  as for Andy.

  But Chuck rolls a three. So after he passes three matches to

  Dave, he still has three left in his bowl. And I note a loss of-0.5

  on the chart.

  Now Dave rolls the die; it comes up as a six. But he only has four matches to pass—the three that Chuck just passed to him

  and one from the last round. So he passes four to Evan. I write

  down a gain of +0.5 for him.

  Evan gets a three on the die. So the lone match on the end of

  the table is joined by three more. Evan still has one left in his

  bowl. And I record a loss of-0.5 for Evan.

  At the end of two rounds, this is what the chart looks like.

  E.M. Goldratt

  The Goal: A Process of Ongoing Improvement

  Captured by Plamen T.

  115

  We keep going. The die spins on the table and passes from

  hand to hand. Matches come out of the box and move from bowl

  to bowl. Andy's rolls are—what else?—very average, no steady

  run of high or low numbers. He is able to meet the quota and

  then some. At the other end of the table, it's a different story.

  "Hey, let's keep those matches coming."

  "Yeah, we need more down here."

  "Keep rolling sixes, Andy."

  "It isn't Andy, it's Chuck. Look at him, he's got five."

  After four turns, I have to add more numbers—negative

  numbers—to the bottom of the chart. Not for Andy or for Ben or

  for Chuck, but for Dave and Evan. For them, it looks like there is

  no bottom deep enough.

  After five rounds, the chart looks like this:

  E.M. Goldratt

  The Goal: A Process of Ongoing Improvement

  Captured by Plamen T.

  116

  "How am I doing, Mr. Rogo?" Evan asks me.

  "Well, Evan . . . ever hear the story of the Titanic?"

  He looks depressed.

  "You've got five rounds left," I .tell him. "Maybe you can pull through."

  "Yeah, remember the law of averages," says Chuck.

  "If I have to wash dishes because you guys didn't give me

  enough matches . . ." says Evan, letting vague implications of

  threat hang in the air.

  "I'm doing my job up here," says Andy.

  "Yeah, what's wrong with you guys down there?" asks Ben.

  "Hey, I just now got enough of them to pass," says Dave.

  "I've hardly had any before."

  Indeed, some of the inventory which had been stuck in the

  first three bowls had finally moved to Dave. But now it gets stuck

  in Dave's bowl. The couple of higher rolls he had in the first five

  rounds are averaging out. Now he's getting low rolls just when he

  has inventory to move.

  "C'mon, Dave, gimme some matches," says Evan.

  Dave rolls a one.

  "Aw, Dave! One match!"

  "Andy, you hear what we're having for dinner tonight?" asks

  Ben.

  "I think it's spaghetti," says Andy.

  "Ah, man, that'll be a mess to dean up."

  "Yeah, glad I won't have to do it," says Andy.

  "You just wait," says Evan. "You just wait 'til Dave gets some good numbers for a change."

  But it doesn't get any better.

  "How are we doing now, Mr. Rogo?" asks Evan.

  "I think there's a Brillo pad with your name on it."

  "All right! No dishes tonight!" shouts Andy.

  After ten rounds, this is how the chart looks . . .

  I look at the chart. I still can hardly believe it. It was a bal-

  anced system. And yet throughput went down. Inventory went

  up. And operational expense? If there had been carrying costs on

  the matches, operational expense would have gone up too.

  What if this had been a real plant—with real customers?

  How many units did we manage to ship? We expected to ship

  thirty-five. But what was our actual throughput? It was only

  twenty. About half of what we needed. And it was nowhere near

  E.M. Goldratt

  The Goal: A Process of Ongoing Improvement

  Captured by Plamen T.

  117

  E.M. Goldratt

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  Captured by Plamen T.

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  the maximum potential of each station. If this had been an actual

  plant, half of our orders—or more—would have been late. We'd

  never be able to promise specific delivery dates. And if we did,

  our credibility with customers would drop through the floor.

  All of that sounds familiar, doesn't it?

  "Hey, we can't stop now!" Evan is clamoring.

  "Yea, let's keep playing," says Dave.

  "Okay," says Andy. "What do you want to bet this time? I'll take you on."

  "Let's play for who cooks dinner," says Ben.

  "Great," says Dave.

  "You're on," says Evan.

  They roll the die for another twenty rounds, but I run out of

  paper at the bottom of the page while tracking Dave and Evan.

  What was I expecting? My initial chart ranged from +6 to -6. I

  guess I was expecting some fairly regular highs and lows, a nor-

  mal sine curve. But I didn't get that. Instead, the chart looks like

  I'm tracing a cross-section of the Grand Canyon. Inventory

  moves through the system not in manageable flow, but in waves.

  The mound of matches in Dave's bowl passes to Evan's and onto

  the table finally—only to be replaced by another accumulating
r />   wave. And the system gets further and further behind schedule.

  "Want to play again?" asks Andy.

  "Yeah, only this time I get your seat," says Evan.

  "No way!" says Andy.

  Chuck is in the middle shaking his head, already resigned to

  defeat. Anyway, it's time to head on up the trail again.

  "Some game that turned out to be," says Evan.

  "Right, some game," I mumble.

  E.M. Goldratt

  The Goal: A Process of Ongoing Improvement

  Captured by Plamen T.

  119

  15

  For a while, I watch the line ahead of me. As usual, the gaps

  are widening. I shake my head. If I can't even deal with this in a

  simple hike, how am I going to deal with it in the plant?

  What went wrong back there? Why didn't the balanced

  model work? For about an hour or so, I keep thinking about what

  happened. Twice I have to stop the troop to let us catch up.

  Sometime after the second stop, I've fairly well sorted out what

  happened.

  There was no reserve. When the kids downstream in the

  balanced model got behind, they had no extra capacity to make

  up for the loss. And as the negative deviations accumulated, they

  got deeper and deeper in the hole.

  Then a long-lost memory from way back in some math class

  in school comes to mind. It has to do with something called a

  covariance, the impact of one variable upon others in the same

  group. A mathematical principle says that in a linear dependency

  of two or more variables, the fluctuations of the variables down

  the line will fluctuate around the maximum deviation established

  by any preceding variables. That explains what happened in the

  balanced model.

  Fine, but what do I do about it?

  On the trail, when I see how far behind we are, I can tell

  everyone to hurry up. Or I can tell Ron to slow down or stop.

  And we close ranks. Inside a plant, when the departments get

  behind and work-in-process inventory starts building up, people

  are shifted around, they're put on overtime, managers start to

  crack the whip, product moves out the door, and inventories

  slowly go down again. Yeah, that's it: we run to catch up. (We

  always run, never stop; the other option, having some workers

  idle, is taboo.) So why can't we catch up at my plant? It feels like

  we're always running. We're running so hard we're out of breath.

  I look up the trail. Not only are the gaps still occurring, but

  they're expanding faster than ever! Then I notice something

  weird. Nobody in the column is stuck on the heels of anybody

  else. Except me. I'm stuck behind Herbie.

  Herbie? What's he doing back here?

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  The Goal: A Process of Ongoing Improvement

  Captured by Plamen T.

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  I lean to the side so I can see the line better. Ron i's no longer

  leading the troop; he's a third of the way back now. And Davey is

  ahead of him. I don't know who's leading. I can't see that far.

  Well, son of a gun. The little bastards changed their marching

  order on me.

  "Herbie, how come you're all the way back here?" I ask.

  "Oh, hi, Mr. Rogo," says Herbie as he turns around. "I just thought I'd stay back here with you. This way I won't hold anybody up."

  He's walking backwards as he says this.

  "Hu-huh, well, that's thoughtful of you. Watch out!"

  Herbie trips on a tree root and goes flying onto his backside.

  I help him up.

  "Are you okay?" I ask.

  "Yeah, but I guess I'd better walk forwards, huh?" he says.

  "Kind of hard to talk that way though."

  "That's okay, Herbie," I tell him as we start walking again.

  "You just enjoy the hike. I've got lots to think about."

  And that's no lie. Because I think Herbie may have just put

  me onto something. My guess is that Herbie, unless he's trying

  very hard, as he was before lunch, is the slowest one in the troop.

  I mean, he seems like a good kid and everything. He's clearly

  very conscientious—but he's slower than all the others. (Some-

  body's got to be, right?) So when Herbie is walking at what I'll

  loosely call his "optimal" pace—a pace that's comfortable to him

  —he's going to be moving slower than anybody who happens to

  be behind him. Like me.

  At the moment, Herbie isn't limiting the progress of anyone

  except me. In fact, all the boys have arranged themselves (delib-

  erately or accidentally, I'm not sure which) in an order that allows

  every one of them to walk without restriction. As I look up the

  line, I can't see anybody who is being held back by anybody else.

  The order in which they've put themselves has placed the fastest

  kid at the front of the line, and the slowest at the back of the line.

  In effect, each of them, like Herbie, has found an optimal pace

  for himself. If this were my plant, it would be as if there were a never-ending supply of work—no idle time.

  But look at what's happening: the length of the line is

  spreading farther and faster than ever before. The gaps between

  the boys are widening. The closer to the front of the line, the

  wider the gaps become and the faster they expand.

  E.M. Goldratt

  The Goal: A Process of Ongoing Improvement

  Captured by Plamen T.

  121

  You can look at it this way, too: Herbie is advancing at his

  own speed, which happens to be slower than my potential speed.

  But because of dependency, my maximum speed is the rate at

  which Herbie is walking. My rate is throughput. Herbie's rate

  governs mine. So Herbie really is determining the maximum

  throughput.

  My head feels as though it's going to take off.

  Because, see, it really doesn't matter how fast any o ne of us

  can go, or does go. Somebody up there, whoever is leading right

  now, is walking faster than average, say, three miles per hour. So

  what! Is his speed helping the troop as a whole to move faster, to gain more throughput? No way. Each of the other boys down the

  line is walking a little bit faster than the kid directly behind him.

  Are any of them helping to move the troop faster? Absolutely not.

  Herbie is walking at his own slower speed. He is the one who is

  governing throughput for the troop as a whole.

  In fact, whoever is moving the slowest in the troop is the one

  who will govern throughput. And that person may not always be

  Herbie. Before lunch, Herbie was walking faster. It really wasn't

  obvious who was the slowest in the troop. So the role of Herbie—

  the greatest limit on throughput—was actually floating through

  the troop; it depended upon who was moving the slowest at a

  particular time. But overall, Herbie has the least capacity for

  walking. His rate ultimately determines the troop's rate. Which

  means—

  "Hey, look at this, Mr. Rogo," says Herbie.

  He's pointing at a marker made of concrete next to the trail.

  I take a look. Well, I'll be ... it's a milestone! A genuine, hon-

  est-to-god milestone! How many speeches have I heard where

  somebody talks about these damn things
? And this is the first one

  I've ever come across. This is what it says:

  <—5—>

  miles

  Hmmm. It must mean there are five miles to walk in both

  directions. So this must be the mid-point of the hike. Five miles to

  go.

  What time is it?

  I check my watch. Gee, it's 2:30 P.M. already. And we left at

  E.M. Goldratt

  The Goal: A Process of Ongoing Improvement

  Captured by Plamen T.

  122

  8:30 A.M. So subtracting the hour we took for lunch, that means

  we've covered five miles ... in five hours?

  We aren't moving at two miles per hour. We are moving at

  the rate of one mile per hour. So with five hours to go ...

  It's going to be DARK by the time we get there.

  And Herbie is standing here next to me delaying the

  throughput of the entire troop.

  "Okay, let's go! Let's go!" I tell him.

  "All right! All right!" says Herbie, jumping.

  What am I going to do?

  Rogo, (I'm telling myself in my head), you loser! You can't

  even manage a troop of Boy Scouts! Up front, you've got some

  kid who wants to set a speed record, and here you are stuck

  behind Fat Herbie, the slowest kid in the woods. After an hour,

  the kid in front—if he's really moving at three miles per hour—is

  going to be two miles ahead. Which means you're going to have

  to run two miles to catch up with him.

  If this were my plant, Peach wouldn't even give me three

  months. I'd already be on the street by now. The demand was for

  us to cover ten miles in five hours, and we've only done half of

  that. Inventory is racing out of sight. The carrying costs on that

  inventory would be rising. We'd be ruining the company.

  But there really isn't much I can do about Herbie. Maybe I

  could put him someplace else in the line, but he's not going to

  move any faster. So it wouldn't make any difference.

  Or would it?

  "HEY!" I yell forward. "TELL THE KID AT THE FRONT

  TO STOP WHERE HE IS!"

  The boys relay the call up to the front of the column.

  "EVERYBODY STAY IN LINE UNTIL WE CATCH UP!" I

  yell. "DON'T LOSE YOUR PLACE IN THE LINE!"

  Fifteen minutes later, the troop is standing in condensed

  line. I find that Andy is the one who usurped the role of leader. I

  remind them all to stay in exactly the same place they had when

  we were walking.

 

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