Measurement in Everyday Language

February 1998 A developer of software or software-related products wants to stay in business—which is strongly tied to customer satisfaction. Customer satisfaction can be expressed in many ways. First and most important, a product should do what the customer wants it to do. In addition, when a customer pays a developer to develop software products, the customer wants these products to be delivered according to some established schedule and for some established amount of money. In this article, we fold considerations such as these into our concept of “product goodness.” For us, then, product goodness is a multidimensional concept that in this article is called integrity. One dictionary definition of integrity is “completeness,” which can be tied to multiple perspectives represented by product attributes. Often, people think of goodness from one perspective, e.g., manager or developer, or in terms of an attribute, e.g., budget, schedule, or requirements. Our integrity concept allows for blending of multiple perspectives. For example, a manager may think of product goodness as the product being delivered on time or within budget or both. A developer may think of product goodness as the product doing what the customer wants. We think of product goodness as product integrity that folds in all the perspectives. As shown in Figure 1, we use the notion of displacement (length of a line) in space to derive the idea of a product integrity index that combines all perspectives into a single number. The space of interest is product attribute space; that is, the axes in product integrity space are product attributes. Figure 1 illustrates this notion of displacement for the case of three attributes. We recognize that the attributes we may choose to fold into our notion of “product integrity” would not necessarily be the same as the attributes you would choose. Consequently, the measurement approach we discuss in this article allows you to mold the product integrity concept to the needs of your organization. This article provides an example set of attributes to define an example product integrity index, a general formula to compute the index, and a summary of how the integrity index concept has been applied in the real world of software systems development.