Maintainability is a major aspect of any software project; maintainability refers to the ease by which software can adapt to changes. There are various factors that affect the effort required for maintenance, in this paper we conducted a study to observe the extent up to which a metric could affect the maintainability of a software. We have considered various versions of JabRef and studied how maintainability of various packages had changed across versions. This is done using a framework called Goal Question Metric(GQM) which provides a systematic procedure to study various attributes of entities. Data of the attributes are collected using various Object-Oriented code metric tools which provide numerical data to compare the attributes between the versions. The data collected is visualized to answer the questions formulated which indeed tends to achieve the goal to identify the modules that are hard to maintain.