Starting More Is How Everything Gets Late

Your line is behind. So you start the next job. Then another. Everyone is busy. Nothing is shipping.

That is not bad luck. It is arithmetic.

THE RULE

In 1961, John D. C. Little proved a simple relationship for any stable system where work comes in and goes out. The average number of jobs inside the system equals how fast they finish times how long each one stays.

Flip it around and it speaks floor language: the time a job spends with you equals the jobs in progress divided by how fast you finish them.

As long as you finish about the same number of jobs per shift, every extra job you start makes every job wait longer. Double what is open, and the average wait doubles. Nobody has to work slower for that to happen.

PICTURE THIS

Picture a second-shift lead whose cell finishes about 20 jobs a shift. Ten jobs are open. Each one takes about half a shift from start to done. Then the lead gets pressure to “get ahead,” and releases ten more. Twenty jobs are open. The cell still finishes 20 a shift. Now every job takes a full shift. The first customer call about a late order comes in. The lead starts more. This is a built example, not a story from a real plant.

THE MISTAKE

We treat starting as progress. A job that is started but not finished has cost you the material, the labor, and the space. It has paid you nothing yet. And it hides problems. When 20 jobs sit open, nobody sees which one is stuck.

WHAT TO DO TOMORROW

1. At start of shift, count what is open on your line right now. Write the number on the board.
2. Pick a cap. Start with the number you have, minus two.
3. Rule for the shift: no new job starts until one finishes.
4. At end of shift, write down how long a job took. Compare it to yesterday.

Two limits to be honest about. The rule holds for averages over a steady stretch, not for a single rush job. And a cap only helps if the work you do finish is the work the customer needs first. Pick that order on purpose. A third limit: do not cap so low that your slowest step sits waiting for work. Watch it for one shift. If it ever stands idle with nothing to run, put one job back in front of it. Finished jobs per shift should hold or rise. If they fall, you cut too deep.

THE SHIFT IS DIFFERENT WHEN

The board shows fewer open jobs, and the stuck one is easy to see. You can answer “when will it ship?” without guessing.

ONE LINE TO TAKE WITH YOU

Stop starting. Start finishing.