Solving a recurring site problem on one page
On a 14-storey residential building, the queue at the base of the construction hoist starts forming at 06:55. By 07:10 on Tuesday, 46 workers are waiting, some beside carts of material, and the level 12 drywall crew reaches its floor at 07:50. The superintendent has raised the queue at three coordination meetings, and each Monday it is back.
Put the problem on one page and work through it in order: measure it, find its cause in the site's routine, try a change that removes the cause, and check with the same measure that it worked. A problem that returns every week comes from the way the site's routine is set up, which is why reminders at meetings do not stick. Use an A3 problem-solving sheet to hold the problem, analysis, actions and check on one page. The Lean Enterprise Institute describes the underlying cycle as plan, do, check and act.
The boxes on the page
- Current state: measure the problem for a week, the same way each day, and set a target. A one-day observation shows where the time goes.
- What happens: draw the routine with the foremen who live with it — who arrives when, what goes up first, where the queue forms.
- Cause: ask why until you reach something in the routine you can change; the method is in finding the cause, not just the defect.
- Countermeasures: changes that remove the cause, each with an owner, run for a fixed trial such as two weeks.
- Check: measure again, the same way. Lean practice ends each cycle by standardizing a change that worked or starting the cycle again, so write what worked into the site rules.
Common mistakes
- Choosing a fix at the first meeting, before anyone has measured the problem.
- A countermeasure that is only a reminder, such as "everyone on time".
- Changing several things and never measuring again.
- Filling in the page in the office, without the foremen.
Action list
This week
- Choose one problem that came back three times this month
- Count it with the foreman who lives with it, starting tomorrow
- Pin a blank A3 sheet where the foremen meet
- Book thirty minutes with them to find the cause
- Set the trial's end date before it starts
- Write any change that works into the site rules
Check your understanding
The staggered starts work for three weeks, then the queue returns in the week a new flooring trade arrives. What does that tell you?
