The quality factor of class diagram is critical because it has a significant influence on overall quality of the product, delivered finally. Testability analysis, when done early in the software creation process, is a criterion of critical importance to software quality. Reusability is an important quality factor to testability. Its early measurement in object oriented software especially at design phase, allows a design to be reapplied to a new problem without much extra effort. This research paper proposes a research framework for quantification process and does an extensive review on reusability of object oriented software. A metrics based model "Reusability Quantification of Object Oriented Design" has been proposed by establishing the relationship among design properties and reusability and justifying the correlation with the help of statistical measures. Also, "Reusability Quantification Model" is empirically validated and contextual significance of the study shows the high correlation for model acceptance. This research paper facilitates to software developers and designer, the inclusion of reusability quantification model to access and quantify software reusability for quality product.

The quality of any object oriented design is critical because it has a great influence on overall quality of finally delivered software product. Testability quantification early in the software development process is a criterion of crucial important to software development team. Testability has always been an indefinable concept its correct measurement, quantification or evaluation is a difficult task because of its potential factors. Testability analysis of object oriented software at an initial stage of software development process has been identified as a key factor for high quality product. A best suited object oriented design (OOD) properties and its associated metrics are helpful if applied in the early stage of development process .This paper describes an improved testability quantification framework using the identified set of potential factors, OOD properties and OOD metrics for software products at early phase, exclusively at design time. The proposed framework relates OOD properties to high level quality attributes/constructs using appropriate information to develop quality product and it may used to benchmark software products according to their key attribute. The objective of this research work to encourage researchers and developers to provide a framework to access and quantify software testability at early stage of development life cycle.

Effectiveness is important quality factor to testability measurement of object oriented software at an initial stage of software development process exclusively at design phase for high quality product. It will help developer's design capability to achieve the specified functionalities, characteristics, better design quality and behavior using appropriate object oriented design (OOD)

The quality factor of class diagram is critical because it has significant influence on overall quality of the product, delivered finally. Testability has been recognized as a key factor to software quality. Estimating testability at design stage is a criterion of crucial significance for software designers to make the design more testable. Taking view of this fact, this paper identifies testability factors namely effectiveness and reusability and establishes the correlation among testability, effectiveness and reusability and justifies the correlation with the help of statistical measures. Moreover study developed metric based testability estimation model and developed model has been validated using experimental test. Subsequently, research integrates the empirical validation of the developed model for high level acceptance. Finally a hypothesis test performs by the two standards to test the significance of correlation.