MichaelK --
If you save a project as a separate Version, such as a Target version (like
the one that is included the sample database), you capture the COMPLETE
project as it existed before beginning work on the project. When the
project is completed, you are compare the finished production project with
the original Target project using the built-in Compare Project Versions
add-in (View - Toolbars - Compare Project Versions). Using this tool, you
can analyze any or all differences between the original and finished
projects, such as whether you added tasks, removed tasks, changed Durations,
etc.
When you baseline a project, Microsoft Project captures the current values
for the Start, Finish, Duration, Work, and Cost fields for each task and
assignment, plus the Cost and Work values for each resource. As the project
progresses, you can compare the current state of the project with its
original baseline by applying the Tracking Gantt view, or one of the three
task variance tables (Work, Cost, and Variance).
Depending on what you hope to accomplish, you could use versioning,
baselining, or both of these. Hope this helps.