Software quality requirements_and_evaluation

Software Development Center
Software Quality
Requirements And Evaluation
Created by: Thao Mai-Thi-Bich
Effective date: December 08, 2012
Version: 1.0
Template ID: N/A

Software Quality Requirements & Evaluation 4
Agenda
Organization Of SQuaRE Series Of International
Standards
1
Targets Of Quality Models3
Structure Used For The Quality Models2
Product Quality Model4
Quality In Use Model5
Data Quality Model6

Agenda
Data Quality Model6
Standards
1

Organization Of SQuaRE Series Of International Standards
Figure 1 — Organization of SQuaRE series of International Standards

ISO/IEC 2500n -ISO/IEC 2500n -
Quality ManagementQuality Management
DivisionDivision
● Define all common models, terms and definitions
● Provides requirements and guidance for a supporting
function that is responsible for the management of the
requirements, specification and evaluation of software
product quality.
Quality Model DivisionQuality Model Division
● Present detailed quality models for computer systems
and software products, quality in use, and data
● Practical guidance on the use of the quality models

Quality MeasurementQuality Measurement
DivisionDivision
Quality RequirementsQuality Requirements
DivisionDivision
● Include a software product quality measurement
reference model, mathematical definitions of quality
measures, and practical guidance for their application
● Help specify quality requirements, based on quality
models and quality measures.
● These quality requirements can be used in the
process of quality requirements elicitation for a
software product to be developed or as input for an
evaluation process.

Quality EvaluationQuality Evaluation
DivisionDivision
● Provide requirements, recommendations and
guidelines for software product evaluation, whether
performed by evaluators, acquirers or developers

Agenda
Standards
1
Data Quality Model6

Structure Used For The Quality Models

Agenda
Standards
1
Data Quality Model6

Targets Of Quality Models

Agenda
Standards
1
Data Quality Model6

Product Quality Model

Product quality model What It Means
Functional suitability
Functional completeness Degree to which the set of functions covers all the specified tasks and user objectives
Functional correctness
Performance efficiency Performance relative to the amount of resources used under stated conditions
Time behaviour
Resource utilization
Capacity
Degree to which a product or system provides functions that meet stated and implied
needs when used under specified conditions
Degree to which a product or system provides the correct results with the needed
degree of precision
Functional
appropriateness
Degree to which the functions facilitate the accomplishment of specified tasks and
objectives
Degree to which the response and processing times and throughput rates of a product
or system, when performing its functions, meet requirements
Degree to which the amounts and types of resources used by a product or system when
performing its functions meet requirements
Degree to which the maximum limits of a product or system parameter meet
requirements

Compatibility
Co-existence
Interoperability
Degree to which a product, system or component can exchange information with other
products, systems or components, and/or perform its required functions, while sharing
the same hardware or software environment
Degree to which a product can perform its required functions efficiently while sharing a
common environment and resources with other products, without detrimental impact on
any other product
Degree to which two or more systems, products or components can exchange
information and use the information that has been exchanged

Usability
Learnability
Operability Degree to which a product or system has attributes that make it easy to operate and control
Performance efficiency Performance relative to the amount of resources used under stated conditions
Time behaviour
Resource utilization
Capacity Degree to which the maximum limits of a product or system parameter meet requirements
Degree to which a product or system can be used by specified users to achieve specified
goals with effectiveness, efficiency and satisfaction in a specified context of use
Appropriateness
recognizability
Degree to which users can recognize whether a product or system is appropriate for their
needs
Degree to which a product or system can be used by specified users to achieve specified
goals of learning to use the product or system with effectiveness, efficiency, freedom from
risk and satisfaction in a specified context of use
Degree to which the response and processing times and throughput rates of a product or
system, when performing its functions, meet requirements
Degree to which the amounts and types of resources used by a product or system when
performing its functions meet requirements

Reliability
Maturity Degree to which a system meets needs for reliability under normal operation
Availability
Fault tolerance
Recoverability
Degree to which a system, product or component performs specified functions under
specified conditions for a specified period of time
Degree to which a system, product or component is operational and accessible when
required for use
Degree to which a system, product or component operates as intended despite the
presence of hardware or software faults
Degree to which, in the event of an interruption or a failure, a product or system can
recover the data directly affected and re-establish the desired state of the system

Security
Confidentiality
Integrity
Non-repudiation
Accountability Degree to which the actions of an entity can be traced uniquely to the entity
Authenticity
Degree to which a product or system protects information and data so that persons or
other products or systems have the degree of data access appropriate to their types
and levels of authorization
Degree to which a product or system ensures that data are accessible only to those
authorized to have access
Degree to which a system, product or component prevents unauthorized access to, or
modification of, computer programs or data
Degree to which actions or events can be proven to have taken place, so that the events
or actions cannot be repudiated later
Degree to which the identity of a subject or resource can be proved to be the one
claimed

Maintainability
Modularity
Reusability
Analysability
Modifiability
Testability
Degree of effectiveness and efficiency with which a product or system can be modified
by the intended maintainers
Degree to which a system or computer program is composed of discrete components
such that a change to one component has minimal impact on other components
Degree to which an asset can be used in more than one system, or in building other
assets
Degree of effectiveness and efficiency with which it is possible to assess the impact on
a product or system of an intended change to one or more of its parts, or to diagnose
a product for deficiencies or causes of failures, or to identify parts to be modified
Degree to which a product or system can be effectively and efficiently modified without
introducing defects or degrading existing product quality
Degree of effectiveness and efficiency with which test criteria can be established for a
system, product or component and tests can be performed to determine whether those
criteria have been met

Portability
Adaptability
Installability
Replaceability
Degree of effectiveness and efficiency with which a system, product or component can
be transferred from one hardware, software or other operational or usage environment
to another
Degree to which a product or system can effectively and efficiently be adapted for
different or evolving hardware, software or other operational or usage environments
Degree of effectiveness and efficiency with which a product or system can be
successfully installed and/or uninstalled in a specified environment
Degree to which a product can be replaced by another specified software product for
the same purpose in the same environment

Agenda
Standards
1
Data Quality Model6

Quality In Use Model

Quality in use model What It Means
Effectiveness Accuracy and completeness with which users achieve specified goals
Efficiency
Satisfaction
Usefulness
Trust
Pleasure Degree to which a user obtains pleasure from fulfilling their personal needs
Comfort Degree to which the user is satisfied with physical comfort
Resources expended in relation to the accuracy and completeness with which users
achieve goals
Degree to which user needs are satisfied when a product or system is used in a
specified context of use
Degree to which a user is satisfied with their perceived achievement of pragmatic
goals, including the results of use and the consequences of use
Degree to which a user or other stakeholder has confidence that a product or system
will behave as intended

Quality in use model What It Means
Economic risk mitigation
Environmental risk mitigation
Context coverage
Context completeness
Flexibility
Freedom from risk Degree to which a product or system mitigates the potential risk to economic status,
human life, health, or the environment
Degree to which a product or system mitigates the potential risk to financial status,
efficient operation, commercial property, reputation or other resources in the intended
contexts of use
Health and safety risk
mitigation
Degree to which a product or system mitigates the potential risk to people in the
intended contexts of use
Degree to which a product or system mitigates the potential risk to property or the
environment in the intended contexts of use
Degree to which a product or system can be used with effectiveness, efficiency,
freedom from risk and satisfaction in both specified contexts of use and in contexts
beyond those initially explicitly identified
freedom from risk and satisfaction in all the specified contexts of use
freedom from risk and satisfaction in contexts beyond those initially specified in the
requirements

Agenda
Standards
1
Data Quality Model6

Data Quality Model

Data Quality Model
 Consistency
 The absence of apparent contradictions within data
 Inconsistency can be verified on the same or different entities
 Example: An employee's birth date cannot be later than his
“recruitment date”
 Currency
 Currency is the extent to which data is up-to-date
 It is critical for volatile data (Ex: frequently updated data, as wind
speed or climate temperature)
 Example 1: When attending a course, a student needs to know
the right timetable before its starting date
 Example 2: A flight seat cannot be available after it has been
assigned to someone; so the flight seat data value must be stored
before another user asks for the same data

 Completeness
 From a computer system's point of view
 The extent to which all necessary values have been assigned
and stored in the computer system
 Refers both to entity occurrences and to attributes of a single
occurrence
 From an end-user perspective
 The extent to which data are sufficiently able to satisfy user's
stated needs from quantitative point of view
 Includes also the capability of data to represent the context
observed by users
 Example: if an entity refers to a company's employees, all the
employees must be recorded with all attributes requested to
satisfy a user's stated needs
Data Quality Model

 Precision
 The capability of the value assigned to an attribute to provide the
degree of information needed in a stated context of use
 Example: to represent the duration of a marathon race the
minimum unit of time must be seconds; to represent the duration
of 100 meters race the minimum unit of time must be milliseconds
 Accuracy
 The degree to which a data value conforms to its actual or
specified value
Data Quality Model

 Accuracy: Two main aspects
 Syntactical accuracy
 The closeness of the data values to a set of values defined in a
domain considered syntactically correct
 Example: a low degree of syntactical accuracy is when the word Mary
is stored as Mary
 Semantic accuracy
 Semantic accuracy is defined as the closeness of the data values to
a set of values defined in a domain considered semantically correct
 Example: a low degree of semantic accuracy is when the name John
is stored as George. Both names are syntactically accurate, because
of the domain of reference in which they reside, but George is a
different name
Data Quality Model

 Security
 The capability of the data to be accessed and interpreted only by
authorized users
 Example: data that refer to personal or confidential information
like health or profit must be accessed only by authorized users or
must be written in secret code
 Availability: The capability of data to be always retrievable
 Note: a particular case of availability is concurrent access (both
to read or to update data) by more than one user and/or
application
 Example: data must be accessible also during managing
operations like backup
Data Quality Model

 Recoverability
 The capability of the data to maintain and preserve a specified
level of operations and its physical and logical integrity, even in
the event of failure
 This standard refers to the quality of data, not the system: the
characteristic of recoverability is related to the data that must be
recoverable
 Note : Recoverability can be provided by features like commit /
synchpoint, rollback (fault-tolerance capability) or by backup-
recovery mechanisms
 Example: when a media device has a failure, data stored in that
device must be recoverable
Data Quality Model

 Understandability
 The extent to which the real meaning of data is easy for users to
comprehend
 The extent to which data is in appropriate languages, symbols and
units, and
 The degree to which data definitions are clear [5], [10]
 Note : some information about data understandability are provided
by metadata
 Example : To represent a State (within a country) , the standard
acronym is more understandable than a numeric code
Data Quality Model

 Manageability
 The capability of data to be stored appropriately from a functional
point of view
 Example : Data representing costs: stored like numeric and not
like string, to allow users to carry out algebraic operations
 Efficiency
 The capability of data to be processed (accessed, acquired,
updated, etc) and to provide appropriate levels of performance
using the appropriate amounts and types of resources under
stated conditions
 Example : Using more space than necessary to store data can
cause waste of storage, memory and time
Data Quality Model

 Changeability
 The capability of data to be modified in its type, length or assigned
value for changes in technological environment, in requirements
or in functional specifications
 Example : changing the “address” attribute in its length must be
allowed if needed
 Portability: Also referred to as “Interoperability”
 The capability of data to be moved from one platform to another;
this includes the capability of data to be also installed and
replaced in its destination platform. It refers particularly to
homogeneous and coherent set of data
Data Quality Model

 Productivity
 The capability of data to enable users to carry out his task in an
efficient way by using an appropriate amount of resources, and
the extent to which data is applicable and helpful for the task
 Data are productive for users when they satisfy the scope and the
goal of his information needs
 Safety
 The extent to which data is related to their capability to achieve an
acceptable level of risk to people, businesses, properties or the
environment in a specified context of use
 Example : data concerning blood group are relevant to users of
health care computer systems
Data Quality Model

 Credibility
 The extent to which data are regarded as true and credible by
users
 Accessibility
 The capability of data to be accessed, particularly by people who
need supporting technology or special configuration because of
some disability.
 Example : data that must be managed by a screen reader cannot
be stored as an image.
 Regulatory compliance
 The capability of data to adhere to standards, conventions or
regulations in force and similar rules relating to data quality.
Data Quality Model

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