Software Quality Management - CiteSeerX

R. Dawson, E. Georgiadou, P. Linecar, M. Ross. G. Staples (eds), Perspectives in Software Quality, Proceeding of the 14th Software Quality Management Conference, (SQM 2006), April, Southampton, UK, ISBN 1-902505-76-X, The British Computer Society, pp. 85-96

Integrating Six Sigma with CMMI for High Quality Software Kerstin V. Siakas 1 , Kleoniki S. Nisioti 2 , Eleni A. Voutsa 3 , Márta Gellén 4

1, 2, 3 Alexander Technological Educational Institute of Thessaloniki,

Department of Informatics, P.O. Box 141, GR-57400 Thessaloniki, Greece Tel: +30 31 791 296, Fax: +30 31 791 290, E-mail: 1 [email protected], 2 [email protected], 3 [email protected]

4 Tata Consultancy Services Ltd., Magyarországi Fióktelepe

1117 Budapest, Irinyi József u. 4-20. Hungary Tel:+36 1 8868 021 E-mail: 4 [email protected]

Abstract Software development has been one of the most difficult challenges faced by many businesses around the world. The rate of failure has been high, leading to reports of a software crisis. The cost of hardware technology has decreased whereas the need for quality software has increased. However, the cost and the quality of software development have not seen comparable improvement. It is generally recognised that high software quality is a difficult and complex concept. Six Sigma is an approach attributed to product and process improvement that has gained wide acceptance and returned large benefits across many industries globally. The Six Sigma methodology provides the techniques as well as tools to improve the capability and reduce the defects in any process. Organisations usually think of Six Sigma as an over-arching “umbrella” under which a large set of tools and methodologies are set. The software industry has mainly used capability improvement methodologies, such as the Capability Maturity Model (CMM®) Integrated (CMMISM), which provides a framework for IT organisations to assess and improve their process capability and maturity. This paper explores Six Sigma and CMMI in terms of their relationships to one another similarities and differences and how a company can blend the two for added value and argues that the Six Sigma methodology when blended with CMMI is likely to enable businesses to effectively overcome the challenges of deployment and deliver optimal results.


1.

Introduction

Globalisation and instant access to information, products and services have changed the way that customers conduct business. Today traditional business models are no longer adequate on their own. Top quality and just-in-time approaches together with low-cost products and services have become core values. Customers’ persistency and search for delight and satisfaction prompt for new ways to fulfil and exceed their expectations. CMMI is one of the most widespread and acknowledged software development process definitions for improving software project performance. Six Sigma is a nondomain specific measurement driven approach to improvement. They both build on the Total Quality Management (TQM) principles and therefore they aim for customer satisfaction and continuous improvement. The goal of a Six Sigma programme is to reduce defects (any problems with service performance or product faults that do not meet the customer specification) to a level that statistically relates to 3.4 defects per million instances or opportunities. In contrast, the fundamental premise behind the CMMI is to improve the quality of a software product by improving the quality of the processes used to build it. CMMI is used as a long term framework for improving the methods and processes used for software product or service development and delivery, whereas Six Sigma is usually used for short term (3-6 months) optimising of selected iterative processes. We argue that the Six Sigma methodology when blended with CMMI is a transition enabler of software and systems best practices. The Six Sigma methodology promises added business value by the creation of a new business culture [1]. CMMI identifies what activities are expected (industry best practices). Six Sigma identifies how activities may be improved for being more efficient and effective. The full potential of the data produced by the CMMI would gain benefits of leverage by using a more comprehensive product and process improvement tool, such as the Six Sigma methodology [2].

2.

The Six Sigma Methodology

There are many definitions of Six Sigma, each depending on the approach to Six Sigma. Most of the definitions state that Six Sigma is a quality management programme that measures and improves the operational performance of a company [3, 4]. Six Sigma is a disciplined measurement and data-driven approach to continuous improvement. Six Sigma entails a quality metric that counts the number of defects per million opportunities [9]. The basic approach is to measure performance on an existing process and compare it with a statistically valid ideal in order to identify how to eliminate any variation. Project teams may speak in terms of reducing cycle time, improving customer satisfaction, cutting down on returns and improving the speed and accuracy of order fulfilment. Today the emphasis in Six Sigma is on the production of a product or a service that satisfies the customer and minimises waste (lean software development) in order to achieve high quality products or services at an affordable price (value-for-money). Statistical implications of a Six Sigma program go beyond the qualitative elimination of customer-perceptible defects. It is a methodology that is rooted in mathematics and statistics. The basic principle of Six Sigma, states that a defect can be defined as anything outside of customer expectations. The Six Sigma approach measures statistically the number of discrepancies in a process and aims to systematically determine how to eliminate them by getting as close to “zero defects” as possible. To achieve Six Sigma quality, a process must produce no more than 3.4 defects per million opportunities (A Six Sigma opportunity is the total number of chances for a defect) [5]. This means that an organisation needs to be nearly flawless in executing its key processes [5]. Six Sigma is the strategic imperative for each organisation that

R. Dawson, E. Georgiadou, P. Linecar, M. Ross. G. Staples (eds), Perspectives in Software Quality, Proceeding of the 14th Software Quality Management Conference, (SQM 2006), April, Southampton, UK, ISBN 1-902505-76-X, The British Computer Society, pp. 85-96 seeks to achieve total customer satisfaction [4]. Metrics are established aligning the strategic goals and values of the organisation to customer's needs and expectations. Hard data are collected and expressed as ratios; soft data, such as attitudes, norms of behaviour, communication levels and other cultural issues that could have an impact on the process, are converted to hard data. However, this process is two-folded: softmetrics are subjective and qualitative and leads us to the need of understanding what soft-issues to extract and how to convert them into hard data. What does the word “Sigma” mean? The Greek letter Sigma stands for "Sophrosyne" meaning "Wisdom"[6], also the word is a statistical term that measures how far a given process deviates from perfection [7] and represents the new standard of excellence based on the statistical measure of variability in any given process. Once the data is acquired the root cause of defects can be identified and eliminated in order to secure a flawless performance. In manufacturing, the number of non-conformance products can easily be quantified. In addition quantification of the process is usually performed with quantification of delays and backlogs. In a service environment the emphasis is basically on process performance. The higher the sigma quality value (defects per million opportunities) the less variation and fewer defects in the process. Six Sigma originated at Motorola in the early 1980s in response to a CEO-driven challenge to achieve tenfold reduction in product-failure levels in five years [8]. Meeting this challenge required rapid and accurate root-cause analysis and correction. In the mid-1990s, Motorola announced the details of their quality improvement framework, which has since been adopted by several large manufacturing companies. A popular approach to Six Sigma is Lean Six Sigma (LSS). Lean Six Sigma is the application of lean techniques to increase organisational speed and to minimize waste, while combining the tools and culture of Six Sigma to improve efficiency and focus on customers’ needs and expectations. The principles of Lean Six Sigma are to initially work on critical quality issues defined by customers and the reasons behind them and those which create the longest time delays in any process [10].

2.1 Six Sigma for new processes or products Six Sigma DMADV depicted in figure 1 is an improvement system that defines, measures, analyses, designs and verifies a process and is used to develop new processes or products at Six Sigma quality levels [8, 11]. The five steps of DMADV process are [11]: ·

Define: Define the project goals and customer (internal and external) deliverables critical to quality

·

Measure: Measure and determine customer needs and specifications

·

Analyse: Analyse the process options to meet the customer needs

·

Design: Design the process in details to meet the customer needs

·

Verify: Verify the design performance and ability to meet customer needs

R. Dawson, E. Georgiadou, P. Linecar, M. Ross. G. Staples (eds), Perspectives in Software Quality, Proceeding of the 14th Software Quality Management Conference, (SQM 2006), April, Southampton, UK, ISBN 1-902505-76-X, The British Computer Society, pp. 85-96 1. Define

5. Verify

2. Measure

DMADV Process

3. Analyse

4. Design

Figure 1: Six Sigma DMADV [adopted from: 11] Six Sigma starts with quantitative business goals that provide value to the customer. Data analysis is used to identify specific processes with the greatest leverage on these goals. The processes are designed in detail to meet customer needs and verified for their ability to meet the requirements.

2.2 Six Sigma for improvement and control of existing processes Six Sigma DMAIC depicted in figure 2 is a process that defines, measures, analyzes, i mproves and controls existing processes that fall below the Six Sigma specification [11]. The five steps of DMAIC process are: ·

Define: A Six Sigma project team identifies a project based on business objectives as well as customer needs and feedback. The team identifies the projects or features that the customer considers to have the highest impact on quality [11]. This is critical for defining and prioritising the quality characteristics. It also separates the “vital few” from the “trivial many”.

·

Measure: The team identifies the key internal processes and measures the defects currently generated relative to those processes.

·

Analyse: The team discovers why defects are generated by identifying the key variables that are most likely to create process variation.

·

Improve: The team identifies the maximum acceptable ranges of the key variables and validates a system for measuring deviations of the variables. The processes are modified to remain within the acceptable range.

·

Control: Tools are put in place to ensure that the key variables remain within the maximum acceptable ranges over time.

R. Dawson, E. Georgiadou, P. Linecar, M. Ross. G. Staples (eds), Perspectives in Software Quality, Proceeding of the 14th Software Quality Management Conference, (SQM 2006), April, Southampton, UK, ISBN 1-902505-76-X, The British Computer Society, pp. 85-96 2. Measure

1. Define

5. Control

DMAIC Process

3. Analyse

4. Improve

Figure 2: Six Sigma DMAIC [adopted from: 11] Having defined an existing process the next phase is to measure its performance. Performance measurements of quality (expressed statistically as the process mean and variation) and throughput (number of items produced, services generated, etc) are carried out. The cost of each step of the process is measured in terms of time and resources. Delay time and transportation expenses between stages are also calculated. The analyse stage that follows include cause and defect analysis as well as analysis of variance. Prototyping and simulations are performed to determine improvements. During the improvement stage improvements are made and measured. The results are compared with the prototype and the simulation results to validate the improvement before it is implemented for the process. The improvement is implemented as an operational change in a controlled manner.

2.3 Six Sigma structure All employees in an organisation that uses the Six Sigma methodology must be trained on Six Sigma Quality in order to increase their work and productivity [12]. The organisation structure in a Six Sigma project is divided into levels (similar to Kung-Fu) called belts, as follow: Champion, Master Black Belt, Black Belt, Green Belt and Yellow Belt [13], although some organisations consider only three belts: the Master Black Belt, Black Belt and Green Belt [14]. The top project manager is usually a Champion, who creates the vision, measures the progress and sustains improvements. The Master Black Belt is a mentor who develops a Six Sigma network and supervises the projects. Black Belt and Green Belt teams demonstrate credible application of Six Sigma tools, train other team members and are accountable for Six Sigma project results. While Black Belts work full-time on Six Sigma projects, the Green Belts work only part-time on the Six Sigma projects and devote the rest of their time to other projects. Yellow Belt is the initial level of Six Sigma training [9, 12, 14].


Figure 3: The Belts of Six Sigma [adapted from: 13] Figure 3 shows the hierarchy of the belts in Six Sigma training. Champ means Champion and MBB means Master Black Belt. The lowest level, the yellow belt, is easiest to obtain and comprises the base for escalation to higher levels.

2.4 Six Sigma in Software Development The Six Sigma methodology is a tool for quality improvement. Software quality is often seen as an elusive and intangible subject; it is in general an ignored topic by software engineers [15]. The implementation of Six Sigma in software development has proved to be quite difficult, because of the nature of the process of software development. Software is usually a unique product, the components of which can be reused to millions of similar software products leaving out the manufacturing process of reproducing multiple items from raw material [30]. In software the complication lies in the first stages of the software development, namely requirements analysis and design, whilst manufacturing is trivial. Software is created by brainpower resulting in quantification and estimation difficulties of factors, such as programming skills, level of expertise (domain knowledge, social awareness and technical experience). In the early years the Software Engineering Community concentrated on the quality of product. Repeated failures of systems and projects shifted the emphasis to the process with noticeable improvement of both process and product. Inevitably what the user sees is the product, irrespective of the process and thus more recently a shift has occurred to include more product focusing, user satisfaction and Just-In-Time (JIT) approaches [16]. Such an example is the appearance of the Agile methodologies in year 2000 [17]. This indicates recognition of the fact that substantial effort, time and costs are required at the beginning of the lifecycle. Six Sigma emphasises the importance of designing quality and reliability from the beginning of the process (i.e. design stage) to the end, the stage of software delivery, i.e. throughout the entire product or service life cycle [15].

3.

The CMMI Methodology

The Capability Maturity Model (CMM®) Integrated (CMMISM) [5] is developed for projects or organisations that wish to assess and improve their Systems and Software processes. CMMI refers to the integration of diverse tool sets and appraisal methods related to CMM. It is a method that provides a set of best practices that address productivity, performance, costs and stakeholder satisfaction. The CMMI is used to transfer proven practices into a structure that helps in assessing its organisational maturity, Processing A rea (PA) capability, establishing priorities for improvement and guiding the implementation of these improvements [18].

R. Dawson, E. Georgiadou, P. Linecar, M. Ross. G. Staples (eds), Perspectives in Software Quality, Proceeding of the 14th Software Quality Management Conference, (SQM 2006), April, Southampton, UK, ISBN 1-902505-76-X, The British Computer Society, pp. 85-96 CMMI provides a consistent, enduring framework that accommodates new initiatives and facilitates enterprise-wide process improvement. Process improvement using the CMMI improves predictability of the critical measures of cost, schedule, performance and customer satisfaction. CMMI is designed to tailor business goals unlike many previous process improvement models [5]. The built-in flexibility of the CMMI provides organisations with the opportunity to set priority areas for initiating a successful capability assessment [5]. The CMMI assessment comprise five maturity levels, namely Initial, Managed, Defined, Quantitatively Managed and Optimizing. Each level is a layer in the foundation for continuous process improvement using a proven sequence of improvements, beginning with basic management practices and progressing through a predefined and proven path of successive levels.

4.

The relationship between Six Sigma and CMMI

The CMMI (Capability Maturity Model Integration) aims at the same goals and principals as Six Sigma. Six Sigma and improvement approaches such as CMMI are complimentary and mutually supportive. Depending on current organizational or individual circumstances, Six Sigma could be an enabler to launch CMMI. The relationship between Six Sigma for Software and CMMI can be best understood as a difference in level of abstraction. ·

Six Sigma for Software might be used to objectively evaluate the overall effect of CMMI on software product quality, cost, and cycle time, whereas the focus in the CMMI is set on the evaluation of the overall technical capability of an organisation. This is carried out through assessment of software processes against a set of criteria to determine the capability of those processes to perform within quality, cost and schedule. In other words, Six Sigma covers CMMI on a broader scope and relates the quality of the process to the product [18]. The use of Six Sigma is in particular useful if the organisation additionally uses an alternative approach, such as the agile methodology [7]. Six Sigma could well be used to select highest priority PAs (levels) within CMMI [15].

The relationship between Six Sigma for Software and CMMI might also be characterised as a difference in goals. The goals of Six Sigma are broader than in CMMI. ·

The primary goals of CMMI are continuous process improvements in terms of placing proven practices into a structure that helps the organisation to assess its maturity of PA capability, to establish priorities for improvement and to guide the implementation of these improvements.

·

The goals of Six Sigma for Software may include the goals of CMMI, but do not specify any particular process definition to achieve those goals [8]. In addition, Six Sigma for Software may be applied to achieve many other business objectives, such as improved customer service after delivery of the software, or improved customer satisfaction and value realisation from the software product features delivered. Six Sigma for Software applies to the software process, the software product, and the balance between the customer needs and the business needs in order to maximize overall business value resulting from the quality of processes and products.

·

An additional distinction is that Six Sigma is typically applied to selected projects, while CMMI is intended for all projects. Six Sigma may, for

R. Dawson, E. Georgiadou, P. Linecar, M. Ross. G. Staples (eds), Perspectives in Software Quality, Proceeding of the 14th Software Quality Management Conference, (SQM 2006), April, Southampton, UK, ISBN 1-902505-76-X, The British Computer Society, pp. 85-96 example, be used to plan and evaluate a pilot implementation of CMMI since it can provide additional information and direction for the creation of a more comprehensive process definition [8] or to achieve additional business objectives. ·

5.

In CMMI people are thought to be roles instead of individuals and the processes are designed to be adjusted by whoever will be in the role, whilst in the Six Sigma methodology people have been trained and are considered to be unique, creative professionals with distinctive “belts”. Such a structure has the implication that organisations striving for CMMI also try to be unaffected by staff turnover, whilst organisations striving for Six Sigma are dependent on expertise, which may create knowledge dilution in case they leave the company. The view of knowledge is currently considered to be human capital that ‘walks out the door at the end of the day” [19]. The problem seems to be the capture of the personal knowledge and to transfer it into the organisational knowledge. The CMMI approach supports Knowledge Management in that it defines, maps and measures processes for continuous improvement.

Integrating Six Sigma and the CMMI

If Six Sigma and CMMI are integrated the advantages of both methodologies will bring added business value through different approach to process improvement. Some organisations do not proceed integrating Lean Six Sigma (LSS) with CMMI until the processes have been defined (Level 3), whereas others use Lean Six Sigma techniques to help define processes during the lower levels of maturity [17]. Others [22] build in Six Sigma as a process / practice in the CMMI. Examples of companies that have integrated Six Sigma with the CMMI are amongst others Motorola, Tata Consultancy Services (TCS) [22], Honeywell [23] and PS&J Software Six Sigma [24]. Motorola Labs [25] used multivariate analysis techniques of Six Sigma to determine the causes of delays in closure of corrective action reports and to improve their audit process. How to apply multivariate techniques to software processes is included in the Motorola University I-Cubed Presentation Series [16]. Motorola has several facilities evaluated at CMMI, Level 5, and is the founder of Six Sigma [26]. In particular TCS applied Six Sigma to their software review process and to decisions on program metrics [27]. This work was done for their Chennai, India, engineering centre for General Electric. This TCS centre has been evaluated as a CMMI, Level 5, organisation. Honeywell and PS&J Software Six Sigma introduced Six Sigma techniques into the Personal Software Process as defined by Humphrey at the Software Engineering Institute [28].

R. Dawson, E. Georgiadou, P. Linecar, M. Ross. G. Staples (eds), Perspectives in Software Quality, Proceeding of the 14th Software Quality Management Conference, (SQM 2006), April, Southampton, UK, ISBN 1-902505-76-X, The British Computer Society, pp. 85-96 Figure 4: Integrating Six Sigma and the CMMI Figure 4 shows the five levels (steps) of CMMI wrapped in a Six Sigma Belt to show that the two approaches are complementary. The Six Sigma toolkit aligns very well with the quantitative process management, product quality management, and process optimisation practices associated with level 4 and 5. However, the use of two approaches may simultaneously create conflicts. CMMI is cited for its ability to create a controlled process for progress into a disciplined and managed software development environment. Six Sigma is noted for the process analysis and statistical skills that assist Black Belts when working with discrete process problems. Motorola and Allied Signal, early adopters of Six Sigma, elected to use the CMMI as a framework to start their software process improvement initiatives. They did leverage their experience with Six Sigma and were among the first enterprises to achieve CMMI Level 4. Ultimately, a blend of the two approaches seems most appropriate, with Six Sigma entering at the higher maturity levels [28].

6.

The Integration in Action

Questionnaires were sent to several companies using Six Sigma and CMMI for gathering information from industry. We received an interesting response from Tata Consultancy Services Ltd, Magyarországi Fióktelepe, a TCS Subsidiary in Hungary. The TATA Consultancy Services (TCS) Ltd., is among the leading global information technology organisations, offering services to clients across 55 countries. The TCS's integrated Quality Management System (iQMS) integrates the practices and standards of various established frameworks and models, including IEEE, ISO 9001:2000, CMMI, SW-CMM, P-CMM, BS7799, BS15000 and Six Sigma. TCS has been using Six Sigma since 1999 and is assessed to Level 5 maturity of CMMI since August 2004. Referring to the use of Six Sigma the organisation has noticed just advantages. More specifically: · Building the culture of process improvements using the Six Sigma · Quantitative approach for decision making and arriving at solutions · Customer Delight by Cycle time reduction · Productivity improvement and Reduced Cost of Quality Referring to the use of CMMI they noticed both advantages and disadvantages. The advantages are listed below: · · · · ·

Well-defined processes to meet the vision/mission/policy of organisation. Building Assets and increasing the re-usability Tailoring processes to meet the customer demands Quantitative approaches in making decisions and arriving at solutions Building robust processes based on suggestions and feedback

the

The organisation was already CMM, Level 5, assessed before they established the CMMI and the People CMM (P-CMM) practices. A difficulty noticed during the change process from CMM to CMMI and P-CMM was stakeholder training, as well as to build up the awareness on the model requirements. This challenge was overcome by having model based training to key roles only. All other associates of the organisation were trained on the internal quality processes and the iQMS. Today the organisation successfully blends the two methodologies, Six Sigma and CMMI. They believe that blending Six Sigma and CMMI increases the quality of

R. Dawson, E. Georgiadou, P. Linecar, M. Ross. G. Staples (eds), Perspectives in Software Quality, Proceeding of the 14th Software Quality Management Conference, (SQM 2006), April, Southampton, UK, ISBN 1-902505-76-X, The British Computer Society, pp. 85-96 their products, because in their case they have built in Six Sigma as a process / practice. During the integration process of Six Sigma and CMMI they have not found any difficulties, on the contrary, they observed that PAs for Level 4 and Level 5, of CMMI, practices are satisfied by adopting Six Sigma methodology. Six Sigma correlations to CMMI PAs can be demonstrated by a GB project, which was worked out in TCS Hungary, and as a result of the improvement the team managed to e n h a n c e t h e productivity. One such case to illustrate the Process Change Management (PCM) - (Part of the Organisational Innovation and Deployment (OID) of CMMI) was to provide AS/400 system availability on 'Saturdays' of Month End weekends and reduce Month End processing time to 65% in order to provide maximum system availability. They found out how they should change the processes by rescheduling the activities in order to reduce the time. Another case of implementation of OID (a Level 5 PA in CMMI) in TCS Hungary is that; at the centre level the process of metrics collection and analysis was automated by which the productivity improvement and cycle time reduction were achieved.

7.

Conclusions

The Six Sigma DMAIC process can be a useful tool to any organisation that attempts to improve its CMMI results. The Design for Six Sigma (DFSS) process can be a useful part of the software process for any organisation with a reasonable level of maturity. Conversely, an organisation seeking to improve its software development process using DMAIC might also consider the CMMI for process improvement opportunities, since certain professional conclude that as soon as DMAIC is applied correctly it produces consistently better results than most methods [14]. The two methods are complementary. Six Sigma provides a welldefined methodology through DMAIC, for improving a processes capability. Through DFSS, it provides a methodology for implementing products or processes that meet the customers’ needs. CMMI provides a measurement framework which can give insight into how a particular software process measures up to best practices. The Six Sigma methodology is the “roadmap” to achieve improvement goals and an “umbrella” over the CMMI and other related tools [29]. Our findings from the literature and the case study are that the Six Sigma toolkit aligns positively with the quantitative process management, product quality management, and process optimisation practices associated with level four and five, concluding us to recommend blending of the two approaches.

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