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  • Writer's pictureJeanette Zocco

The Six Sigma Roadmap

Updated: May 19

Six Sigma

Six Sigma is a quality improvement model developed by Motorola in 1985. Sigma refers to standard deviation. Six Sigma represents the three standard deviations above and below the mean, also known as upper and lower control limits. The name reflects a tightly-controlled process with little variation (Kelly et al., 2018). The goal of Six Sigma is twofold: Find and remove defects in processes, and develop processes that can be carried out the same way every time. A process is in control when statistical analysis shows variability occurs within three standard deviations above and below the mean, resulting in an extremely low defect rate (Kelly et al., 2018). This article describes the six sigma roadmap and describes one hospitals experience using this model to reduce bed turnaround time.


The Six Sigma roadmap is a set of problem-solving steps known as DMAIC: Define, Measure, Analyze, Improve, and Control.

• Define – Describe the team, variable, and baseline data, the goal to reach once variation is reduced, and the project schedule.

Measure – Assess baseline data, decide what will be measured, and determine who will make measurements. This step may use pareto and process control charts.

Analyze – Review data to identify themes and determine causes for errors. Control charts and fishbone diagrams are useful tools in this step.

Improve – Develop solutions to reduce variation. Trial these solutions on a small scale.

Control – Develop ways to sustain the initiative, such as continued monitoring of data and employee education, whether occurring at the outset, offering periodic refresher workshops, and/or building it into new employee orientation.

(Kelly et al., 2018)

One Hospital's Experience Using Six Sigma

North Shore University Hospital in Manhasset, New York, used Six Sigma to reduce bed turnaround time for admitted patients. Bed turnaround time referred to the time between one patient receiving discharge instructions and the admission RN being notified a clean bed was available.

Quality improvement focused on one surgical unit, which accepted patients from the ED, critical care, and PACU. The unit’s problems included communication among team members, inefficient processes, the role of environmental services, and a discrepancy between who was supposed to control the process and who was actually controlling the process.

Opportunities for improved communication between RNs and other team members were identified. It was discovered that admission RNs were using an inefficient process to determine availability of a clean bed, including conducting unit rounds, making phone calls, and reviewing census information. Many assumed that environmental services contributed significantly to delays in bed turnaround time, but the bed tracking system revealed that environmental services was cleaning a room within 55 minutes of patient discharge, which exceeded the national standard. Lastly, the process uncovered that a clerical support associate controlled the bed turnaround process, but according to policy, it was not their responsibility.

Applying the DMAIC steps looked like this:

Define – The QI focus was turnaround time, beginning with the time a patient

received discharge instructions to the time the admission RN was notified that a clean bed was available. A goal time of 120 minutes was established, with an upper limit of 150 minutes.

Measure – A process map identified steps in the process. The time required for each step was tracked. Baseline data determined that the current turnaround time was 226 minutes.

Analyze – The data was divided according to where patients were discharged: to home or to rehabilitation. The team decided to evaluate turnaround time only for patients who were discharged home, because with this subgroup, more factors remained in the hospital’s control. Data was analyzed using statistical measures (analysis of variance and a two sample t-test), and technical and communication opportunities were identified. Incorrect use of the bed tracking system, along with lack of communication between care team members and the admission RN regarding clean bed status, were creating delays.

Improve – The team enacted solutions, included the following:

o Re-education on the bed tracking system, integrated into orientation and annual competency.

o System changes to provide instant notification of a clean bed including tracking communication between admission RNs and care team members, adding bed tracking system cheat sheets, and connecting the admission RN beeper system to the bed tracking system.

The mean turnaround time was reduced from 226 minutes to 90 minutes.

Control – Data was monitored monthly, showing continued improvement.

(Pellicone & Martocci, 2006)

*If this article interests you, you may also enjoy my book titled: Obstetric and Neonatal Quality and Safety (C-ONQS) Study Guide: A Practical Resource for Perinatal Nurses, available on Amazon, click below to access:

Copyright by Jeanette Zocco MSN RNC-OB, C-EFM, C-ONQS


Kelly, P., Vottero, B. A., & Christie-McAuliffe, C. A. (2018). Introduction to quality and safety education for nurses: Core competencies for nursing leadership and management. Springer Publishing Company.

Pellicone, A. & Martocci, M. (2006). Faster Turnaround Time. Quality Progress, 31-36. Retrieved from

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