“…In their study, logical change size is defined as the commit size as measured by the number of files changed, while structure changes are defined as the differences in the file dependency graphs obtained by comparing daily snapshots. Hattori and Lanza (2008) confirmed that commit size, measured by the number of changed files, closely fol- Power law also exits in many other measures of software systems, such as the number of methods, fields, constructors, subclasses, instance variable names and method names (Wheeldon and Counsell, 2003;Concas et al, 2007;Turnu et al, 2011), as well as the number of bugs in a module .…”