  Software engineering is continuously facing the challenges of growing
complexity of software packages and increased level of data on defects and
drawbacks from software production process. This makes a clarion call for
inventions and methods which can enable a more reusable, reliable, easily
maintainable and high quality software systems with deeper control on software
generation process. Quality and productivity are indeed the two most important
parameters for controlling any industrial process. Implementation of a
successful control system requires some means of measurement. Software metrics
play an important role in the management aspects of the software development
process such as better planning, assessment of improvements, resource
allocation and reduction of unpredictability. The process involving early
detection of potential problems, productivity evaluation and evaluating
external quality factors such as reusability, maintainability, defect proneness
and complexity are of utmost importance. Here we discuss the application of CK
metrics and estimation model to predict the external quality parameters for
optimizing the design process and production process for desired levels of
quality. Estimation of defect-proneness in object-oriented system at design
level is developed using a novel methodology where models of relationship
between CK metrics and defect-proneness index is achieved. A multifunctional
estimation approach captures the correlation between CK metrics and defect
proneness level of software modules.
