June 2002
Volume 4 • Number 3

Contents

SOFTWARE QUALITY MANAGEMENT
A Taxonomy to Compare Software Process Improvement Frameworks
By Christian Printzell Halvorsen, Galaxy Republic and Reidar Conradi Norwegian University of Science and Technology

The principle behind software process improvement (SPI) is that product quality is strongly influenced by the quality of the associated software process for development and maintenance. A number of SPI frameworks have evolved from this principle. These frameworks, however, are comprehensive and differ in a variety of aspects, making them difficult to compare objectively. This article addresses four methods that can be used to compare SPI frameworks. The authors have explored one of them further and propose a simple and pragmatic SPI framework taxonomy. Their taxonomy consists of 25 relevant characteristics, which can be used to point out framework similarities and differences on a high level. An example of how the taxonomy can be applied to six common SPI frameworks is provided.

Key words: CMM, EF/QIP/GQM, ISO 9000, ISO/IEC 15504, software process improvement (SPI), SPIQ, TQM

INTRODUCTION

More and more people are realizing that the most critical challenges in software development are not purely technical. As for all engineering work, many problems lie in the interaction between technology and organization. Schedule and budget overruns are common, as are delivered software products with insufficient or unwanted functionality, poor reliability, inefficiency, and so on. These are serious deficiencies related to the development process. Evolution of software needs and requirements as well as an overall unpredictability are major challenges (Humphrey 1989; Sørumgård 1997; SPICE 1998).

Software process improvement (SPI) sprung out as a solution to these process-related difficulties. The assumption behind SPI and the many SPI frameworks is that product quality is influenced by the quality of the process used to develop it. People should therefore focus their improvement efforts on the software process in order to improve software quality. This can explicitly be expressed by the following causal relation:

Quality (Process) —> Quality (Product) (1)

The words quality and process are vital to the authors’ discussion of SPI. Readers are encouraged to refer to other sources such as (Emam, Drouin, and Melo 1997; Humphrey 1989; Lonchamp 1993; Zahran 1998) for more information:

• Quality. Good quality implies happy users. However, Kitchenham (1996) states that quality “is hard to define, impossible to measure, easy to recognize.” Nevertheless, most SPI frameworks specify a measurable (process) quality indicator from which process quality can be inferred.
  
• Software process. “...a set of partially ordered process steps, with sets of related products, human and computerized resources, organizational structures, and constraints intended to produce and maintain the requested software products” (Lonchamp 1993).

It is interesting to note that many of the differences between SPI frameworks stem from different interpretations of these two words.

The full text of this article may be found in the print journal. To subscibe go to /quality-press/display-item/index.html?item=SUBSCR_SQP.

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