Quality Improvement Methods
49. Takt Time
a. Definition: The concept of Takt time (based on a German phrase Taktzeit for meter or pace) is to balance workloads so that flow is continuous. This will help maximize throughput and minimize wasteful inventories between steps, in the case of over production, as well as idle time, in the case of under production. Takt time is determined by calculating the ratio of time available to work during a given period, such as a day, divided by demand (units) for that time period. For example, the overall Takt time for a hospital laboratory would be the available hours in a day divided by the number of procedures to be done in a day resulting in an hourly rate necessary to meet the demand. The pace of work is then equalized among each step that is involved by assigning tasks accordingly.
Much of the literature on Lean describes Takt time, such as in the following:
- Jackson, Thomas Lindsay. Standard Work for Lean Healthcare. CRC Press, 2011. (This book does not focus on Takt time but it describes its use and related methods)
- Raisinghani, Mahesh S., et al. "Six Sigma: concepts, tools, and applications." Industrial Management & Data Systems 105.4 (2005): 491-505.
- Crane, Jody, and Chuck Noon. The definitive guide to emergency department operational improvement: employing lean principles with current ED best practices to create the "no wait" department. CRC Press, 2011. (Discusses Takt time and other methods from this handbook as applied to a hospital emergency department.)
c. Example: Patients are to be screened in a clinic following a new set of procedures, as in the research example proposal in Section III. The clinic needs to serve 25 patients who arrive during a 4 hour clinic's day. Since the screening takes 17 minutes there will need to be 1.8 (or two) clinic staff available (25 patients x 17 minutes/patient) / (4 hours x 60 minutes/hour). This will assure that the capacity meets the demand. The patients will need to be served every 9.6 minutes ((4 hours x 60 minutes/hour) / (25 patients)), the Takt time for the clinic.
Another example: The patient flow in surgery was subject to delays, idle time and patient dissatisfaction due to excessive wait time. A hospital improved the flow so it was more continuous and smooth by reviewing the requirements in each step: registration, pre-op, staging, surgery, recovery and discharge. By balancing the workload and required pace in each area there was a net increase in daily throughput with very little change in total labor requirement. This was accomplished by moving certain tasks from one step to another. Of course, some tasks could not be moved, but enough tasks were moveable and changes in staffing could be done to achieve continuous flow.
1) Determine the demand, i.e., what volume is required each day or hour or other time period for a particular type of work being studied.
2) Determine the available productive time (excluding breaks, meeting times, etc.) to service the demand.
3) Calculate the Takt time for the day (or other time period).
4) Compare the Takt time for a particular step to the Takt times for other steps in the sequence of steps so as to level the time requirements in each. For example, in the graph below, work could be moved into steps B and C from the other steps to create a smoother workflow.