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ISO/IEC 15504 also known as SPICE (Software Process Improvement and Capability Determination) is a "framework for the assessment of software processes" developed by the Joint Technical Subcommittee between ISO (International Organization for Standardization) and IEC (International Electrotechnical Commission).

ISO/IEC 15504 derives from ISO 12207 and uses many of the ideas of CMMI.

Overview

The ISO/IEC 15504 framework does not set out specific standards. Other, more specific standards, set out requirements for (say) a valid test plan. What ISO/IEC 15504 is concerned about is the capability provided by the organization's management and process definition structures.

ISO/IEC 15504 is not a methodology. Although ISO/IEC 15504 sets out a list of activities that might (and should) occur in a software project, it does not set out the order in which such activities should be carried out.

ISO/IEC 15504 is, in effect, a set of categories (pigeon holes) in which the assessors can place the evidence that they collect during their assessment, so that the assessors can give an overall determination of the organisation's capabilities for delivering software.

ISO/IEC 15504 has been developed by the Joint Technical Subcommittee between ISO (International Organization for Standardization) and IEC (International Electrotechnical Committee).

The ISO/IEC 15504 standard

The Technical Report (TR) document for ISO/IEC 15504 is divided into 9 parts.

Part 1 of ISO/IEC TR 15504 explains the concepts and gives an overview of the framework.

Reference model

ISO/IEC 15504 contains a reference model. The reference model defines a process dimension and a capability dimension.

The reference model is the subject of part 2 of ISO/IEC TR 15504.

Processes

The process dimension defines processes divided into the five process categories of:

• customer-supplier
• engineering
• supporting
• management
• organization

Capability levels and process attributes

For each process, ISO/IEC 15504 defines a capability level on the following scale:

The capability of processes is measured using process attributes. The international standard defines nine process attributes:

• 1.1 Process Performance
• 2.1 Performance Management
• 2.2 Work Product Management
• 3.1 Process Definition
• 3.2 Process Deployment
• 4.1 Process Measurement
• 4.2 Process Control
• 5.1 Process Innovation
• 5.2 Process Optimization.

Each process attribute is assessed on a four-point (N-P-L-F) rating scale:

• Not achieved (0 - 15%)
• Partially achieved (>15% - 50%)
• Largely achieved (>50%- 85%)
• Fully achieved (>85% - 100%).

Assessments

ISO/IEC 15504 provides a guide for performing an assessment.

This includes:

• the assessment process
• the model for the assessment
• any tools used in the assessment
• success factors

Performing assessments is the subject of parts 3 and 4 of ISO/IEC TR 15504. Part 3 is the normative part and part 4 gives a guidance to fulfill the requirements (deleted by tiot)

Assessment model

The assessment model is the detailed model that is used for an actual assessment. This is an elaboration of the reference model.

Part 5 of ISO/IEC TR 15504 provides an assessment model, but other models could be used instead, if they meet ISO/IEC 15504's criteria.

Assessors

For a successful assessment, the assessor must have a suitable level of the relevant skills.

These skills include:

• personal qualities such as communication skills
• relevant education and training and experience
• specific skills for particular categories, e.g. management skills for the management category.
• training and experience in software capability assessments.

The competency of assessors is the subject of part 6 of ISO/IEC TR 15504.

Uses of ISO/IEC 15504

ISO/IEC 15504 can be used in two contexts:

• Process improvement, and
• Capability determination (= evaluation of supplier's process capability).

Process improvement

ISO/IEC 15504 can be used to perform process improvement within a technology organization. Process improvement is always difficult, and initiatives often fail, so it is important to understand the initial baseline level, and to assess the situation after an improvement project. ISO 15504 provides a standard for assessing the organization's capacity to deliver at each of these stages.

In particular, the reference framework of ISO/IEC 15504 provides a structure for defining objectives, which facilitates specific programs to achieve these objectives .

Process improvement is the subject of part 4 of ISO/IEC 15504.

Capability determination

An organization considering outsourcing software development needs to have a good understanding of the capability of potential suppliers to deliver.

ISO/IEC 15504 can also be used to inform supplier selection decisions. The ISO/IEC 15504 framework provides a framework for assessing proposed suppliers, as assessed either by the organization itself, or by an independent assessor.

The organization can determine a target capability for suppliers, based on the organization's needs, and then assess suppliers against this profile. This is particularly important in contexts where the organization (for example, a government department) is required to accept the cheapest qualifying tender. This also enables suppliers to identify gaps between their current capability and the level required by a potential customer, and to undertake improvement to make the contract. Work on extending the value of capability determination includes a method called Practical Process Profiles - which uses risk as the determining factor in setting target profiles. Combining risk and processes promotes improvement with active risk reduction, hence reducing the likelihood of problems occurring.

Supplier process evaluation has been merged into Part 4 of ISO/IEC 15504.

History

A working group was formed in 1993 to draft the international standard and used the acronym, SPICE. SPICE initially stood for "Software Process Improvement and Capability Evaluation", but French concerns over the meaning of the last word meant that SPICE now means "Software Process Improvement and Capability Determination".

Even though the formal ISO standards number, ISO 15504, is now the correct reference, SPICE is still used for the user group of the standard, and the title for the annual conference. The first SPICE was held in Limerick, Ireland in 2000, "SPICE 2003" was hosted by ESA in Netherlands, "SPICE 2004" was hosted in Portugal, "SPICE 2005" was hosted in Austria, and "SPICE 2006" was hosted in Luxembourg.

The first versions of the standard were focused exclusively on software development processes. This was expanded to cover all related processes in a software business, for example, project management, configuration management, quality assurance, and so on. The list of processes covered, grew to cover six business areas:

• organizational
• management
• engineering
• acquisition supply
• support
• operations.

In a major revision to the draft standard in 2004, the process reference model was removed and is now related to the ISO 12207 (Software Lifecycle Processes). The issued standard now specifies the measurement framework and can use different process reference models. There are five general and industry models in use.

Acceptance of ISO/IEC 15504

ISO/IEC 15504 has been successful as:

• In 2006 GM and Chrysler have started phasing out CMMI in favor of SPICE as they relocate their engineering centers to Europe.
• ISO/IEC 15504 is publicly available through National Standards Bodies.
• It has the support of the international community
• Over 4000 assessments have been performed to date
• Major sectors are leading the pace such as automotive, space and medical systems with industry relevant variants
• Domain-specific models like Automotive SPICE can be derived from it
• There have been many international initiatives to support take-up such as SPICE for small companies.

On the other hand, ISO/IEC 15504 has not been very successful, as compared to the CMMI. This has been for several reasons:

• ISO/IEC 15504 is not available as free download but must be purchased from the ISO. (Automotive SPICE on the other hand can be freely downloaded from the link supplied below.) CMM and CMMI are available as free downloads from the SEI website.
• The CMMI is actively sponsored (by the US Department of Defense).
• The CMM was created first, and reached critical 'market' share before ISO 15504 became available.
• The CMM has subsequently been replaced by the CMMI, which incorporates many of the ideas of ISO/IEC 15504, but also retains the benefits of the CMM.

Like the CMM, ISO/IEC 15504 has been created in a development context, making it difficult to apply in a service management context. But work has started to develop an ITIL-based process reference model that can serve as a basis for a process assessment model. In addition there are methods available that adapt its use to various contexts .

References

• Process Assessment and ISO 15504 ISBN 0-387-23172-2
• Process Assessment and Improvement ISBN 0-387-23182-X

External links

• ISO 15504 Appraisal Assistant Tool
• Spice home page
• ISO/IEC 15504 Assessor Training
• ISO 15504 News (isospice)
• Automotive SPICE
• ISO 15504 Books
• Implementation of Programming Research IRqA to support Automotive Spice
• older draft documents
• Draft-Standard as free download (zipped .doc)

• Software development process
• ISO standards