From data to models yet another modeling of software quality and productivity

Software systems are often subdivided into the levels: application concept, data processing concept and implementation. Evaluation, measurement and assessment have to take these three levels into consideration. Quality models have to consider active and passive elements of the software as well as dynamic characteristics on all three levels. Since software systems and software projects are unique, quality models have to be flexible. A scheme for quality modeling uses weight functions to define quality factors in terms of evaluation factors. With respect to levels of software description a number of ratios are defined in order to describe software quantitatively. Using functions which reflect past experience, it becomes possible to generate estimates over the product extent and the production effort