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Labour and productivity

Timing the first run of a repetitive task to set a realistic rate

By Review.LivePublished 3 min readHow we write

The plumbing rough-in for a 48-room hotel is scheduled at 7 hours a bathroom, a figure carried over from the estimate. The foreman has never roughed in this layout of back-to-back bathrooms. If the real figure is 10, the schedule is wrong 48 times.

Unfinished concrete-block walls and framed openings show repeated masonry work.
Photo: Michael Quinn / National Park Service on Wikimedia Commons · Grand Canyon, Bright Angel Trailhead Restroom Construction 0414 - Flickr - Grand Canyon NPS · CC BY 2.0 · Cropped, resized, colour adjusted and sharpened.

Before you commit to a rate for work that repeats, run the first few units as a planned trial: time each step, change the method where the time goes, and set the rate from the improved runs, not from the estimate or the first unit. The Lean Construction Institute calls this a first-run study: a trial run of the process to find the best means, methods and sequence, done at least a few weeks before production, while there is still time to get different material, tools or people. The first unit carries the learning; the rate should come from the method you settle on, before it is repeated dozens of times.

Plan, do, check, act

  1. Plan the trial a few weeks ahead: release two or three units early, with the production run's material, tools and people. Pair it with the first-installation inspection, which checks quality while this sets method and time.
  2. Time each step of the first unit as you watch, and every interruption for fetching, waiting or redoing.
  3. Review the times with the crew that day: why each step is done, where, in what order and by whom. The crew usually knows where the time went.
  4. Change the method where the time goes: kit the material, pre-assemble at a bench, reorder steps.
  5. Time the second and third units, and keep the changes that held.
  6. Set the rate from the improved runs, for the schedule (see durations from quantities) and the crew's daily target, and write the method on one page with photos.

Common mistakes

  • Scheduling at the estimate's rate without trying the real layout.
  • Setting the rate from the first unit.
  • Timing only the total, so nobody sees which step took the time.
  • Running the trial on the first day of production, too late to change material or tools.

Action list

For the next repetitive task

  1. Release two or three units early
  2. Time every step of the first
  3. Review the times with the crew that day
  4. Change the method where the time goes
  5. Time the next units
  6. Set the rate from the improved runs

Check your understanding

The first unit took 11 hours and the second 9. The superintendent wants to schedule the rest at 9. What do you ask for first?

Show the answer
One or two more timed units. The second unit still carried some learning, and the third shows whether the changes hold. A rate fixed one unit too early can be an hour a unit wrong, across dozens of units.

Sources

  1. Glossary (First-run Study)Lean Construction Institute · accessed

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