The relationship between ISO/IEC 15504 process capability levels, ISO 9001 certification and organization size: An empirical study

Abstract The gradual spread in the use of ISO 9001 and ISO/IEC 15504 (also known as software process improvement and capability determination (SPICE)) has raised questions such as “At what ISO/IEC 15504 capability level would one expect an ISO 9001 certified organization's processes to be?” and “Is there any significant difference between the ISO/IEC 15504 capability levels achieved by the processes of ISO 9001 certified organizations and those of non ISO 9001 certified organizations?”. This paper provides answers to those questions as well as to the following question “Is there any significant difference in the capability levels achieved by the ISO/IEC 15504 processes of organizations with a large information technology (IT) staff and those with a small IT staff?” In order to answer these questions, we analyzed a data set including 691 process instances (PIs) taken from 70 SPICE phase 2 trial assessments performed over the two years from September 1996 to June 1998. Results show that the ISO/IEC 15504 processes of the ISO 9001 certified organizations attained capability levels of around 1–2.3 in 15504 terms. Results also show differences between the capability levels achieved by ISO 9001 certified organizations and non ISO 9001 certified organizations, as well as between organizations with a large IT staff and those with a small IT staff.