The advantages of the software process improvement assessment method as described by Watts Humphrey in Managing the Software Process involve the following.
(1) A Focus on the Reliability of the Organization as a Whole
An assessment does not measure how well individual projects in an organization may have performed, perhaps due to the special insight of a project manager or a happy combination of circumstances. Rather, it measures the capability of the organization as a whole to produce processes and products at a high level. Assessments therefore measure not how well individual projects are currently being implemented but rather the organization’s global capability to replicate good work. The result of a capability maturity assessment is not a rating (like a manufacturing audit) of how well a particular set of procedures are followed, but rather of the capability or potential of the whole organization (based on its systematic implementation of core procedures) to initiate and complete projects in a measured and reliable way. A capability maturity assessment carefully selects representative projects across the breadth and depth of an organization. In Humphrey’s words, "The objectives of software process management are to produce products according to plan while simultaneously improving the organization’s capability to produce better products" .
(2) Encouraging Creativity and Initiative by Emphasizing Goals Instead of Means
An assessment evaluates the functioning of organizational practices with regard to goals, not means. This is crucial. By doing so, it encourages the kind of creativity and initiative that is not only central to the success of good work but also is a key to an organization’s ability to change. The main function of old-fashioned audits, Humphrey notes, was "to ensure that the professionals follow the officially approved process." But, he notes, "typical process deviations are not motivated by greed but by a desire to get the job done as quickly and effectively as practical. The professionals often find that some aspects of the official process are outmoded and inefficient. They properly try to get the job done in spite of these bureaucratic obstacles, and their expedient shortcuts often turn out to be very effective. Thus unless it is done extremely well, an audit can actually do more harm than good, particularly if the official process is either not defined or cannot be implemented as stated" . Assessments allow practitioners to defend and get credit for their initiative and encourage them to imagine change in terms not only of local conditions but also of their own insights into how the job might be done better. It is through such flexibility that an assessment becomes a true lever for change.
(3) An Action-Oriented Approach
An assessment is not only an analysis but also an impetus for an action plan designed for maximum immediate effect. In Humphrey’s words, its "action orientation keeps the questions focused on current problems and the need to solve them." And its staging ensures that any impulse toward positive change is recognized and engaged: "Prior to an assessment the professionals generally are aware of their worst problems and often assume management…doesn’t understand the issues and cannot be expected to solve them. After an assessment, this is no longer the case. An expert study has heard their concerns and suggestions for what should be done about them…After all this, any manager who does not take action will be seen by the people as either incompetent or unconcerned with their problems…In net, management must either focus on taking action or not do an assessment" .
Humphrey’s name for what the SEI now calls CBA IPI and SCAMPI was originally "Software Process Assessment." In Humphrey’s words, "Process assessment helps software organizations improve themselves by identifying their critical problems and establishing improvement priorities." Humphrey argues that process assessment principles must include: "1. The need for a process model as a basis for the assessment. 2. The requirement for confidentiality. 3. Senior management involvement. An attitude of respect for the views of the people in the organization" .