External Quality Metrics for Object-Oriented Software: A Systematic Literature Review

Software quality metrics can be categorized into internal quality, external quality, and quality in use metrics. Although exist close relationship between internal and external software quality, there are not explicit evidences in literature that attributes and metrics of internal quality impact external quality. This is essential to know which metric to use according to the software characteristic that you want to improve. Hence, we carried out a systematic literature review for identifying this relationship. After analyzing 664 papers, 12 papers were studied in depth. As result, we found 65 metrics related to maintainability, usability, reliability, and quality characteristics as well as main attributes that impact external metrics (size, coupling, and cohesion). In follow, we filtered some metrics that have clear definitions, are appropriately related to the characteristic that purports to measure, and do not use subjective attributes in their computation. Therefore, these metrics are more robust and reliable to evaluate software characteristics. So, these metrics are better for use in practice by professionals working in the software market.