Lean manufacturers know that working in small batches speeds the pace of work through any process and increases throughput. In project work, it can be difficult to see the batches, let alone think about making them smaller. A carpenter hanging drywall in the rooms of a hotel project does not put their completed work on a pallet and send it to the painter to do the next step. Builders typically think of their work as a continuous stream without clear starting and stopping points. They work their way through the project, room to room and floor to floor, until all their work is completed. Multiple operations overlap each other, and it can be very difficult to visualize the flow of work or size of a batch. Project-driven organizations rarely plan or execute their work in batches, and when they do, the batches are large, like the entire floor of a building. Workflow is even more difficult to see in non-physical work such as engineering or architecture, and we often see the same large-batch thinking in design work. An architect knows that the plans must be ready for submittal to the city in five months. Although the work passes through the hands off many different designers, they rarely divide the project into small batches to improve the flow.
When we explain the idea of small batches to clients, we use this simple diagram to illustrate how this approach increases speed of work flowing through the system. In the first diagram, five trades work their way through this five-story building in large batches – one floor at time. As each trade completes their work on one batch, they move on to the next, with subsequent trades following just one batch behind them. When the drywaller is beginning work on the fifth floor, the casework installer is just getting started on the first floor. If each trade takes five days to complete a floor, the project will take 45 days to complete.
The second diagram shows the impact of dividing the same scope of work into smaller batches. Our example uses a batch size of one-fifth of a floor. With that approach, the trades follow much closer together, and the casework installer starts their first batch on the fifth floor while the drywaller completes the last batch on the fifth floor. Each trade still takes five days per floor, but each is now just one day ahead of the next. This approach requires additional coordination and careful planning, and the results are almost always worth it. The project using the small-batch approach finishes in only 29 days, a schedule reduction of 35%. Smaller batches ALWAYS move faster!
Years ago, when I was starting to learn about lean thinking in construction, I would have said that using smaller batches is only possible on work that is highly repetitive, like the interiors of a hotel, apartment or medical office building. Today, I realize that creating smaller batches makes sense on every project. The work of dividing a project into batches, determining the workload for each trade partner, and setting a consistent takt time for the completion of each batch, causes a level of coordinated planning that always helps the project. Even when the batches are not as small as we’d like, the outcome is a more well-coordinated team that can execute reliably and achieve much smoother workflow.
Challenge yourself and your team to break their next phase into smaller pieces and see what it does for your project. You might be surprised at the impact!