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Posts Tagged ‘Six Sigma

Using 3σ Control Limits in Software Engineering

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Source: Wikipedia; Control Chart

The  July/August 2010 issue of IEEE Software features an article entitled “Monitoring Software Quality Evolution for Defects” by Hongyu Zhang and Sunghun Kim. The article is of interest to the software developer/tester/manager in quite a few ways. In particular, the authors report on their successful use of 3σ control limits in c-charts used to plot defects in software projects.

To put things in perspective, consider my recent assessment of the results accomplished by Quick Solutions (QSI) in two of their projects:

One to one-and-a-half standard deviation better than the mean might not seem like much to six-sigma black belts. However, in the context of typical results we see in the software industry the QSI results are outstanding.  I have not done the exact math whether those results are superior to 95%, 97% or 98% of software projects in Michael Mah‘s QSMA database as the very exact figure almost does not matter when you achieve this level of excellence.

A complementary perspective is provided by Capers Jones in Estimating Software Costs: Bringing Realism to Estimating:

Another way of looking at six-sigma in a software context would be to achieve a defect-removal efficiency level of about 99.9999 percent. Since the average defect-removal efficiency level in the United States is only about 85 percent, and less than one project in 1000 has ever topped 98 percent,  it can be seen that actual six-sigma results are beyond the current state of the art.

The setting of control limits is, of course, quite a different thing from the actual defect-removal efficiency numbers reported by Jones for the US and the very low number of defects reported by Mah for QSI. Having said that, driving a continuous improvement process through using 3σ control limits is the best recipe toward eventually reaching six-sigma results. For example, one could drive the development process by using Cyclomatic complexity per Java class as the quality characteristic in the figure at the top of this post. In this figure, a Cyclomatic complexity reading higher than 10.860 (the Upper Control Limit) will indicate a need to “stop the line” and attend to reducing complexity before resuming work on functions and features.

Coming on the heels of the impressive results reported by David Joyce on the use of statistical process control (SPC) techniques by the BBC, the article by Zhang and Kim is another encouraging report on the successful application of manufacturing techniques to software (and to knowledge work in general). I am not at liberty to quote from this just published IEEE article, but here is the abstract:

Quality control charts, especially c-charts, can help monitor software quality evolution for defects over time. c-charts of the Eclipse and Gnome systems showed that for systems experiencing active maintenance and updates, quality evolution is complicated and dynamic. The authors identify six quality evolution patterns and describe their implications. Quality assurance teams can use c-charts and patterns to monitor quality evolution and prioritize their efforts.

Beautiful Quality

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Figure 1: Agile Assessment – Quality (Source: QSMA)

Colleague and friend Michael Mah has kindly shared with me the figure above – quality assessment for a sample of Agile projects in the QSMA metrics database of more than 8000 software projects. The two red squares in this figure represent the recent results Mah measured on two projects carried out by Quick Solutions (QSI) – a Westerville, OH company offering a broad range IT services.

One to one-and-a-half standard deviation better than the mean might not seem like much to six sigma black belts. However, in the context of typical results we see in the software industry the QSI results are outstanding.  I have not done the exact math whether those results are superior to 95%, 97% or 98% of software projects in the QSMA database as the very exact figure almost does not matter when you achieve this level of excellence.

I asked Bart Murphy – QSI’s Vice President of Delivery and Operations – for the ‘secret sauce.’ Here is the QSI recipe:

For the projects referenced in Michael’s evaluation, our primary focus was quality…  Our team was tasked with not only a significant Innovation effort, but we also managed all aspects of supporting and stabilizing the application (production support, triage, infrastructure, database support, etc.).  Our ‘secret sauce’ was assembling a world class team and executing our Agile methodology.  We organized the team efforts to focus on the three major initiatives; Innovation, Stabilization (Technical Debt), and Production Support.  We developed a release plan and coordinated efforts to deploy releases that resolved a significant number of defects, introduced market differentiating features, and addressed massive amount of technical debt.  The team was able to accomplish this without introducing additional defects into the production system.   Our success can be attributed to the commitment from the business to understand our Agile methodology and being highly engaged throughout the project (co-located with the team).  In addition, the focus of quality that is integrated into our process through the use of Test Driven Development, Continuous Integration, Test Automation, Quality Assurance, and Show & Tells.  Lastly, this would not have been possible without the co-location of the entire team given the significant issues and time constraints for delivery.

Bart also provided me with a table  ‘a la Capers Jones’ in which he elaborates on the factors that helped QSI achieve these results and those that stood in the way. I will publish and discuss Bart’s table in a forthcoming post. As part of this post I will also compare the factors identified by Bart with those reported by Capers Jones.

The Agile Flywheel

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Readers of The Agile Executive have been exposed to the “All In!” strategy used by Erik Huddleston to transform the software engineering process at Inovis and make it uniquely streamlined. In this post we follow up on the original discussion of the subject to explore the effect of Agile on IT Operations. As the title implies, Agile at Inovis served as a flywheel which created the momentum required to transform IT Operations and blend the best of Agile with the best of ITIL.

This guest post was written by Ray Riescher – a Six Sigma Black Belt, Agile evangelist and a business process change agent. Ray is currently responsible for business process management and IT governance at Inovis, a  leading provider of business-to-business (B2B) e-commerce services, in Alpharetta, GA

Here is Ray:

When we converted to an Agile Scrum software methodology some 24 months ago, I never imagined the lessons I’d learn and the organizational change that would be driven by the adoption of Scrum.

I’ve lived by the philosophy that managing a business is managing its processes and that all of those processes, especially the operational processes, are interconnected.  However, I don’t think I was fully prepared for effect Agile Scrum would have on our company operations.

We dove head first into Agile Scrum and adapted to it very quickly. However, it wasn’t until we landed a very large and demanding customer that Scrum was really put to the test. New enhancements, new features, and new configurations were all needed ASAP.  Scrum delivered with rapid development and deployment in the form of releases that were moving into production with amazing velocity. Our release cadence hit warp drive and at one point we experienced several months where multiple teams’ production releases were deploying at the end of every two week sprint.

We’ve subscribed to the ITIL service support processes for Release, Change, Incident, Problem and Configuration Management. ITIL has served us well, giving us a common language and a clear understanding of process boundaries.

As the Scrum release cadence kicked in, the downstream ITIL processes had to keep up, adapt, and support the dynamics of rapid production changes.  What happened was enlightening and maybe a bit ground breaking.

The Release Management process had to reassess its reliance on artifacts for gate keeping. The levels of sign offs had to be streamlined, the heavyweight deployment documentation had to be lightened, yet the process still had to control the production release to ensure deployment success.  The rapidity of the release cycles meant that maintenance window downtime would be experienced too frequently by customers, so “rolling bounce” deployment strategies were devised and implemented.

Change requests could no longer wait for a weekly Change Management review board to approve and schedule the changes.  Change management risk models had to be relied on for accurate detection of risky changes.

Early on in this dynamic environment, we weren’t quite as good as we needed to be and our Incident Management process was put to the test.  Faster releases meant more opportunity for problems with service degradation and outages. This reality manifested itself more frequently than we’d ever experienced. Monitoring, detecting and repairing became paramount for environment stability and customer satisfaction.

What we found out was that we became very agile at this break/fix game. We developed a small team approach to managing incidents and leveraged the ITIL Problem Management process to rapidly perform root cause analysis. Once the true root cause was determined, a fix would be defined and deployed. Sometimes the fix was software related and went through the Scrum process, sometimes the fix was hardware related and went through the Configuration Management process, other times it was more operational and the fix took the form of training or corrections to procedural documentation.

The point is we’ve become agile across the entire IT spectrum. Whether it’s development via Scrum, the velocity with which we now operate our ITIL processes, or the integrated break/fix operational support processes, we are performing all of these with an agile mindset and discipline. We have small teams, working on priorities, and completing what needs to be completed now.

Scrum set the flywheel in motion and caused the rest of the IT process life cycle to respond.  ITIL’s processes still form the solid core of service support and we’ve improved the processes’ capability to handle intense work velocity. The organization adapted by developing unprecedented speed in the ability to deliver production fixes and to solve root cause problems with agility.

What I think we are witnessing is a manifestation of Agile Business Service Management; a holistic agile methodology running across the IT process spectrum that’s delivering eye popping change and tremendous results.

An Update on Agile Business Service Management

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A previous post in this blog defined the demarcation line between The Agile Executive and BSM Review as follows:

If software development is your primary interest, you might find my forthcoming posts in BSM Review go a little beyond the traditional scope of software methods. If, however, you are interested in software delivery in entirety, you are likely to find good synergy between the topics I will address in BSM Review and those I will continue to bring up in The Agile Executive. Either way, I trust my posts and Cote’s will be of on-going interest to you.

Since writing these words, I realized how tricky it is to adhere to this differentiation. The difficulty lies in the “cord” between development and operations. Development needs to devise algorithms that take into account operational characteristics in IT. Operations needs to comprehend the limits of such algorithms in the context of the service level agreements and operational level agreements that had been negotiated with their customers (either external or internal). The mutual need is particularly strong in the web application/web operations domain where mutual understanding, collaborative work and joint commitment often need to transcend organizational lines.

Given the inherently close ties between development and operations, here are some BSM Review articles and posts that are likely to be of interest to readers of The Agile Executive:

It is a little premature at this early stage to project how BSM Review will evolve. My hunch is that forthcoming articles in BSM Review on cloud computing, large-scale operations, leadership, risk mitigation and technology trends will be of particular interest to readers of this blog.