One of the most important metrics that we use to measure the size of a Visual Basic 6.0 code base to be migrated is called Effective Lines of Code.  This measurement represents all those lines that will require a certain amount of migration effort and in the case of Visual Basic 6.0 to .NET migrations, it includes the following:

• Visual Basic 6.0 code lines: this is the main component of the code base to be migrated and denotes all those VB6 code lines written by the programmers of the source application.

• Visual lines of code: this includes all the code that is automatically generated by the VB6 forms designer.  This code belongs to .frm and .ctl files and is not visible to the programmer (if you open a .frm or .ctl file in a text editor such as Notepad, you will see this visual code at the beginning of the file).  The reason why we include this as part of the code base to be migrated is that VB6 user interface also represents a manual migration effort, together with VB6 source code.

Naturally, the Effective Lines of Code metric does not include blank or comment lines since they do not imply any migration effort.