How to Use Six Sigma to Complement ITIL v3

This is the final instalment in the three-part series on Six Sigma as it applies to Information Technology. You can find the first two parts here at and here. In this part, author Linh Ho explains how you can apply Six Sigma practices to the Infrastructure Library.

In the previous two articles, we looked at what Six Sigma is and how it can be applied to ITSM (IT service management) by highlighting relevant techniques. The techniques described in the previous article are those that are commonly used by IT shops whether their companies are Six Sigma-committed at the corporate level or not. In this article, we will look at what ITIL (Information Technology Infrastructure Library) is, its new version 3's CSI (Continual Service Improvement), and how Six Sigma complements ITIL v3.

ITIL is the industry best practice for ITSM. It was developed in the 1980s in the United Kingdom and widely adopted by the mid- to late 1990s globally. Six Sigma was also developed in the 1980s but has roots in America and has been widely adopted with much success by Global and Fortune 1000 companies.

While ITIL helps establish consistent processes, Six Sigma improves process quality by eliminating defects. The two approaches are a powerful combination for continual IT service improvement. ITIL's service management life cycle focuses on integrating IT with the business-in recognition that IT plays an integral part of the business today. It has five core books supporting this life cycle: Service Strategy, Service Design, Service Transition, Service Operation and CSI. Underpinning these five ITIL phases, there are 24 processes-each with its own objectives and best practice guidelines for process efficiency and for delivering business value of IT services. Six Sigma focuses on the criticality of the business while reducing variation/defects (or costs). At its core is the DMAIC (Define, Measure, Analyze, Improve, Control) model. Each of these phases has clear objectives, tasks and techniques.

Furthermore, Six Sigma provides IT with a way to baseline service quality level, prioritize and focus on what's important to the business/customers, quantify improvement for return on investments, and control improvement. Lastly, Six Sigma comes from the business world with great success while ITIL comes from the world of IT. Combining the two approaches, therefore, helps IT become more aligned with the needs of the business.


Six Sigma

Combined benefits

Establishes consistent processes

  • Focus on IT/business integration

-Service strategy

-Service design

-Service transition

-Service operation

-Continual service improvement

Improves process/service quality

  • Focus on CTQ (critical to quality
  • Reduce variation/ defects/costs






Improved IT process efficiency, service quality while minimizing costs.

Guidelines (what?)

  • five books
  • 24 processes supporting the life cycle

Techniques (how?)

  • VoC (voice of the customer)
  • Pareto charts
  • Failure modes and effects analysis
  • Control charts
  • Process sigma value

Improved communication with the business counterparts and metrics selection.

  • Baseline service quality
  • Prioritize and focus on CTQ
  • Quantify improvement for ROI
  • Sustain improvement

Comes from IT

Comes from the business

Better integration/alignment between IT and the business.

ITIL needs other industry accepted practices (Six Sigma, Cobit, TQM, ISO).

Six Sigma is more efficient with available data to analyze.

Improvement projects are more effective due to the large volume of data in the world of IT.

Table 1 How Six Sigma complements ITIL

Six Sigma and ITIL Continual Service Improvement

CSI is an important phase in the IT Service Management life cycle; since business demands evolve and change over time, the ability to continually meet and exceed the business/customers' expectations becomes critical. ITIL v3 introduces the Seven Step Process to improvement:

1. Define what you should measure

2. Define what you can measure

3. Gather the data

4. Process the data

5. Analyze the data

6. Present/assess the data

7. Implement corrective actions

ITIL also highlights the need for service measurement and reporting through service management products. Moreover, ITIL suggests that other industry-accepted practices such as Six Sigma and Total Quality Management are complementary to further enhance the best practice.

Six Sigma is a widely accepted practical approach for service quality improvement that lends itself naturally to ITIL. The diagram below illustrates how Six Sigma and ITIL v3 CSI fit together.

ITIL v3's new Seven Step Improvement Process in the CSI phase goes hand-in-hand with Six Sigma's DMAIC model. Each of the seven steps is a task typically described under the DMAIC phases (see Figure 1). As described previously, each DMAIC phase has its goals, tasks and tools. If we look at each one of the Six Sigma DMAIC objectives and the seven steps of ITIL's CSI below, we can see where they fit with each other.

Six Sigma Define: Identify the problem. Define measurable goals and end results.

  • ITIL advises in Steps 1 and 2 to define what you should measure and define what you can measure.

Six Sigma Measure: Benchmark current performance. Collect data.

  • ITIL Step 3 is gathering the data.

Six Sigma Analyze: Identify root cause of problem. Analyze the data and identify improvement opportunities.

  • ITIL Steps 4 and 5 are to process the data collected and analyze it so that IT can make decisions during the next steps.

Six Sigma Improve: Recommend and implement solutions. Produce action plan.

  • ITIL Steps 6 and 7 are to present the data analyzed, assess it, draw recommendations for improvement and take corrective actions.

Six Sigma Control: Sustain improvement. Predict process behavior.

  • ITIL does not provide an eighth step to sustain improvement; Six Sigma complements it by adding the Control phase to the Seven Step Improvement Process. Six Sigma provides tools such as Control Charts for ongoing measurement and reporting to maintain improvement until new improvement opportunities arise. This provides a continual cycle for service quality improvement.

Figure 1 This diagram illustrates how ITIL v3's CSI Seven Step Improvement Process complements Six Sigma's DMAIC model.

ITIL v3's emphasis on CSI recognizes the need to add a quality layer to ITSM and bring in proven methods such as Six Sigma and Total Quality Management. Six Sigma complements ITIL by providing tools and techniques to measure, analyze and report on service quality, identify root causes, and prioritize improvement where it matters the most to the customers and business. In short, ITIL establishes consistent ITSM processes, and Six Sigma improves these processes and service quality.

This completes our series of articles on the topic of Six Sigma for ITSM. Some key takeaways from these articles are:

  • Six Sigma is the proven business-driven quality method that brings priority and focus to the business bottom line for IT management.
  • Six Sigma helps IT eliminate recurring problems/defects that impact customers or the business.
  • Six Sigma has key techniques that are immediately applicable for ITSM, whether the company is Six Sigma-committed or not.
  • Large ITSM vendors such as Compuware have automated Six Sigma techniques incorporated in their solutions.
  • Six Sigma complements ITIL and its new CSI phase.

Linh C. Ho is Director of Product Marketing at OpTier Inc. Prior to OpTier, Linh was senior product marketing manager at Compuware, as well as at Proxima Technology. Linh has over 10 years in the IT service management market. Linh is a co-author of two itSMF books: "Global Best Practices for IT Management" and "Six Sigma for IT Management." Linh also served on the review team for several itSMF books, including ITIL V3 Foundations. She has written articles and spoken at conferences on the topics of Six Sigma, ITIL and IT service management. Linh is certified ITIL v3 and a Six Sigma Champion. She holds an Honors Baccalaureate in Commerce; International Business Management and Management Information Systems from the University of Ottawa. She can be reached at

Further reading:

Linh C. Ho has published a Six Sigma Q&A (click here for PDF)

itSMF has published a book called "Six Sigma for IT Management" relating to this topic.