Article: ISO/IEC 9126 Software engineering — Product quality was an international standard for the evaluation of software quality. It has been replaced by ISO/IEC 25010:2011.
The fundamental objective of the ISO/IEC 9126 standard is to address some of the well-known human biases that can adversely affect the delivery and perception of a software development project. These biases include changing priorities after the start of a project or not having any clear definitions of "success". By clarifying, then agreeing on the project priorities and subsequently converting abstract priorities (compliance) to measurable values (output data can be validated against schema X with zero intervention), ISO/IEC 9126 tries to develop a common understanding of the project's objectives and goals.
The standard is divided into four parts:
quality model external metrics internal metrics
quality in use metrics.
Quality
The quality model presented in the first part of the standard, ISO/IEC 9126-1,
classifies software quality in a structured set of characteristics and sub-characteristics as follows:
Functionality - "A set of attributes that bear on the existence of a set of functions and their specified properties. The functions are those that satisfy stated or implied needs."
Suitability Accuracy Interoperability Security Functionality compliance
Reliability - "A set of attributes that bear on the capability of software to maintain its level of performance under stated conditions for a stated period of time."
Maturity Fault tolerance Recoverability Reliability compliance
Usability - "A set of attributes that bear on the effort needed for use, and on the individual assessment of such use, by a stated or implied set of users."
Understandability Learnability Operability Attractiveness Usability compliance
Efficiency - "A set of attributes that bear on the relationship between the level of performance of the software and the amount of resources used, under stated conditions."
Time behaviour Resource utilization Efficiency compliance
Maintainability - "A set of attributes that bear on the effort needed to make specified modifications."
Analyzability Changeability Stability Testability Maintainability compliance
Portability - "A set of attributes that bear on the ability of software to be transferred from one environment to another."
Adaptability Installability Co-existence Replaceability Portability compliance
Each quality sub-characteristic (e.g. adaptability) is further divided into attributes. An attribute is an entity which can be verified or measured in the software product. Attributes are not defined in the standard, as they vary between different software products.
Software product is defined in a broad sense: it encompasses executables, source code, architecture descriptions, and so on. As a result, the notion of user extends to operators as well as to programmers, which are users of components such as software libraries.
The standard provides a framework for organizations to define a quality model for a software product. On doing so, however, it leaves up to each organization the task of specifying precisely its own model. This may be done, for example, by specifying target values for quality metrics which evaluates the degree of presence of quality attributes.
Internal Metrics
Internal metrics are those which do not rely on software execution (static measure).
External metrics
External metrics are applicable to running software.
Quality-in-use metrics
Quality-in-use metrics are only available when the final product is used in real conditions. Ideally, the internal quality determines the external quality and external quality determines quality in use.
This standard stems from the GE model for describing software quality, presented in 1977 by McCall et al., which is organized around three types of quality characteristic:
Factors (to specify): They describe the external view of the software, as viewed by the users.
Criteria (to build): They describe the internal view of the software, as seen by the developer.
Metrics (to control): They are defined and used to provide a scale and method for measurement.
ISO/IEC 9126 distinguishes between a defect and a nonconformity, a defect being "The nonfulfilment of intended usage requirements", whereas a nonconformity is "The nonfulfilment of specified requirements". A similar distinction is made between validation and verification, known as V&V in the testing trade.
History
ISO/IEC 9126 was issued on December 19, 1991.
On June 15, 2001, ISO/IEC 9126:1991 was replaced by ISO/IEC 9126:2001 (four parts 9126–1 to 9126–4).
On March 1, 2011, ISO/IEC 9126 was replaced by ISO/IEC 25010:2011 Systems and software engineering - Systems and software Quality Requirements and Evaluation (SQuaRE) - System and software quality models. Compared to 9126, "security" and "compatibility" were added as main characteristics.
Developments
ISO/IEC then started work on SQuaRE (Software product Quality Requirements and Evaluation), a more extensive series of standards to replace ISO/IEC 9126, with numbers of the form ISO/IEC 250mn. For instance, ISO/IEC 25000 was issued in 2005, and ISO/IEC 25010, which supersedes ISO/IEC 9126-1, was issued in March 2011. ISO 25010 has eight product quality characteristics (in contrast to ISO 9126's six), and 31 subcharacteristics.
"Functionality" is renamed "functional suitability". "Functional completeness" is added as a subcharacteristic, and "interoperability" and "security" are moved elsewhere. "Accuracy" is renamed "functional correctness", and "suitability" is renamed "functional appropriateness".
"Efficiency" is renamed "performance efficiency". "Capacity" is added as a subcharactersitic.
"Compatibility" is a new characteristic, with "co-existence" moved from "portability" and "interoperability" moved from "functionality".
"Usability" has new subcharacteristics of "user error protection" and "accessibility" (use by people with a wide range of characteristics). "Understandability" is renamed "appropriateness recognizability", and "attractiveness" is renamed "user interface aesthetics".
"Reliability" has a new subcharacteristic of "availability" (when required for use).
"Security" is a new characteristic with subcharacteristics of "confidentiality" (data accessible only by those authorized), "integrity" (protection from unauthorized modification), "non-repudiation" (actions can be proven to have taken place), "accountability" (actions can be traced to who did them), and "authenticity" (identity can be proved to be the one claimed).
"Maintainability" has new subcharacteristics of "modularity" (changes in one component have a minimal impact on others) and "reusability"; "changeability" and "stability" are rolled up into "modifiability".
"Portability" has "co-existence" moved elsewhere.
See also CISQ ISO/IEC 25010 ISO 9000 Verification and Validation Non-functional requirements Squale
ISO/IEC JTC 1/SC 7
Software quality References
Scalet et al., 2000: ISO/IEC 9126 and 14598 integration aspects: A Brazilian viewpoint. The Second World Congress on Software Quality, Yokohama, Japan, 2000. |
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CHAPTER 8:Project Quality Management
aaron peñaflor · Follow 8 min read · Sep 2, 2017 -- Listen Share ISO 9126-Quality Management
Software engineering — Product quality
was an international standard for the evaluation of software quality.
The fundamental objective of the ISO/IEC 9126 standard is to address some of the well known human biases that can adversely affect the delivery and perception of a software development project. These biases include changing priorities after the start of a project or not having any clear definitions of “success”. The standard is divided into four parts which addresses, respectively, the following subjects:
Quality model
- classifies software quality in a structured set of characteristics and sub-characteristics as follows:
Functionality
— “A set of attributes that bear on the existence of a set of functions and their specified properties. The functions are those that satisfy stated or implied needs.”
Reliability
— “A set of attributes that bear on the capability of software to maintain its level of performance under stated conditions for a stated period of time.”
Usability
— “A set of attributes that bear on the effort needed for use, and on the individual assessment of such use, by a stated or implied set of users.”
Efficiency
— “A set of attributes that bear on the relationship between the level of performance of the software and the amount of resources used, under stated conditions.”
Maintainability
— “A set of attributes that bear on the effort needed to make specified modifications.”
Portability
— “A set of attributes that bear on the ability of software to be transferred from one environment to another.”
External Metrics
- Internal metrics are those which do not rely on software execution (static measure).
Internal Metrics
-external metrics are applicable to running software.
Quality in use Metrics
-quality-in-use metrics are only available when the final product is used in real conditions. Ideally, the internal quality determines the external quality and external quality determines quality in use.
This standard stems from the GE model for describing software quality, presented in 1977 by McCall et al., which is organized around three types of quality characteristic:
Factors (to specify): They describe the external view of the software, as viewed by the users.
Criteria (to build): They describe the internal view of the software, as seen by the developer.
Metrics (to control): They are defined and used to provide a scale and method for measurement.
Myers-Briggs Personality Type
Myers-Briggs theory was developed by the mother-daughter partnership of Katharine Briggs and Isabel Briggs Myers. It is an adaptation of the theory of psychological types produced by Carl Gustav Jung. There is a lot of depth in the theory but, at its simplest, it consists of 16 types.
At the heart of Myers Briggs theory are four preferences. Do you prefer to deal with:
People and things (Extraversion or “E”), or ideas and information (Introversion or “I”).
Facts and reality (Sensing or “S”), or possibilities and potential (Intuition or “N”).
Logic and truth (Thinking or “T”), or values and relationship (Feeling or “F”).
A lifestyle that is well-structured (Judgment or “J”), or one that goes with the flow (Perception or “P”)
The 16 MBTI Types:
ISTJ- Quiet, serious, earn success by thoroughness and dependability. Practical, matter-of-fact, realistic, and responsible. Decide logically what should be done and work toward it steadily, regardless of distractions. Take pleasure in making everything orderly and organized — their work, their home, their life. Value traditions and loyalty.
ISFJ- Quiet, friendly, responsible, and conscientious. Committed and steady in meeting their obligations. Thorough, painstaking, and accurate. Loyal, considerate, notice and remember specifics about people who are important to them, concerned with how others feel. Strive to create an orderly and harmonious environment at work and at home.
INFJ- Seek meaning and connection in ideas, relationships, and material possessions. Want to understand what motivates people and are insightful about others. Conscientious and committed to their firm values. Develop a clear vision about how best to serve the common good. Organized and decisive in implementing their vision.
INTJ- Have original minds and great drive for implementing their ideas and achieving their goals. Quickly see patterns in external events and develop long-range explanatory perspectives. When committed, organize a job and carry it through. Skeptical and independent, have high standards of competence and performance — for themselves and others.
ISTP- Tolerant and flexible, quiet observers until a problem appears, then act quickly to find workable solutions. Analyze what makes things work and readily get through large amounts of data to isolate the core of practical problems. Interested in cause and effect, organize facts using logical principles, value efficiency.
ISFP- Quiet, friendly, sensitive, and kind. Enjoy the present moment, what’s going on around them. Like to have their own space and to work within their own time frame. Loyal and committed to their values and to people who are important to them. Dislike disagreements and conflicts, do not force their opinions or values on others.
INFP- Idealistic, loyal to their values and to people who are important to them. Want an external life that is congruent with their values. Curious, quick to see possibilities, can be catalysts for implementing ideas. Seek to understand people and to help them fulfill their potential. Adaptable, flexible, and accepting unless a value is threatened.
INTP- Seek to develop logical explanations for everything that interests them. Theoretical and abstract, interested more in ideas than in social interaction. Quiet, contained, flexible, and adaptable. Have unusual ability to focus in depth to solve problems in their area of interest. Skeptical, sometimes critical, always analytical.
ESTP- Flexible and tolerant, they take a pragmatic approach focused on immediate results. Theories and conceptual explanations bore them — they want to act energetically to solve the problem. Focus on the here-and-now, spontaneous, enjoy each moment that they can be active with others. Enjoy material comforts and style. Learn best through doing.
ESFP- Outgoing, friendly, and accepting. Exuberant lovers of life, people, and material comforts. Enjoy working with others to make things happen. Bring common sense and a realistic approach to their work, and make work fun. Flexible and spontaneous, adapt readily to new people and environments. Learn best by trying a new skill with other people.
ENFP- Warmly enthusiastic and imaginative. See life as full of possibilities. Make connections between events and information very quickly, and confidently proceed based on the patterns they see. Want a lot of affirmation from others, and readily give appreciation and support. Spontaneous and flexible, often rely on their ability to improvise and their verbal fluency.
ENTP- Quick, ingenious, stimulating, alert, and outspoken. Resourceful in solving new and challenging problems. Adept at generating conceptual possibilities and then analyzing them strategically. Good at reading other people. Bored by routine, will seldom do the same thing the same way, apt to turn to one new interest after another.
ESTJ- Practical, realistic, matter-of-fact. Decisive, quickly move to implement decisions. Organize projects and people to get things done, focus on getting results in the most efficient way possible. Take care of routine details. Have a clear set of logical standards, systematically follow them and want others to also. Forceful in implementing their plans.
ESFJ- Warmhearted, conscientious, and cooperative. Want harmony in their environment, work with determination to establish it. Like to work with others to complete tasks accurately and on time. Loyal, follow through even in small matters. Notice what others need in their day-by-day lives and try to provide it. Want to be appreciated for who they are and for what they contribute.
ENFJ- Warm, empathetic, responsive, and responsible. Highly attuned to the emotions, needs, and motivations of others. Find potential in everyone, want to help others fulfill their potential. May act as catalysts for individual and group growth. Loyal, responsive to praise and criticism. Sociable, facilitate others in a group, and provide inspiring leadership.
ENTJ- Frank, decisive, assume leadership readily. Quickly see illogical and inefficient procedures and policies, develop and implement comprehensive systems to solve organizational problems. Enjoy long-term planning and goal setting. Usually well informed, well read, enjoy expanding their knowledge and passing it on to others. Forceful in presenting their ideas.
Ishikawa Diagram/Cause-Effect Diagram
Diagrams that helps you visually diagram a problem or condition’s root causes, allowing them to truly diagnose the problem rather than focusing on symptoms. It allows you to separate a problem’s content from its history, and allows you for consensus around the problem and its causes.
Check-Sheet
Is a simple document that is used for collecting data in real time and at the location where the data is generated. The document is typically a blank form that is designed for the quick, easy, and efficient recording of the desired information, which can be either quantitative or qualitative.
Scatter Diagram
The scatter diagram graphs pairs of numerical data, with one variable on each axis, to look for a relationship between them. If the variables are correlated, the points will fall along a line or curve. The better the correlation, the tighter the points will hug the line.
Histogram
Histogram is a display of statistical information that uses rectangles to show the frequency of data items in successive numerical intervals of equal size. In the most common form of histogram, the independent variable is plotted along the horizontal axis and the dependent variable is plotted along the vertical axis. The data appears as colored or shaded rectangles of variable area.
Pareto Chart
Chart that contains both bars and a line graph, where individual values are represented in descending order by bars, and the cumulative total is represented by the line.
Cross-function Flowchart
Is a business process mapping tool used to articulate the steps and stakeholders of a given process.
Run Chart
Run charts are used to visually analyze processes according to time or sequential order. They are useful in assessing process stability, discovering patterns in data, and facilitating process diagnosis and appropriate improvement actions.
Six Sigma
“Six Sigma is a quality program that, when all is said and done, improves your customer’s experience, lowers your costs, and builds better leaders. —
Jack Welch
Six Sigma is a method that provides organizations tools to improve the capability of their business processes. This increase in performance and decrease in process variation lead to defect reduction and improvement in profits, employee morale, and quality of products or services. Is a disciplined, data-driven approach and methodology for eliminating defects (driving toward
six
standard deviations between the mean and the nearest specification limit) in any process — from manufacturing to transactional and from product to service.
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