In general, comparing baselines in different projects is not useful, since the two sets of items do not overlap. However, if you are practicing Requirements Reuse, comparing baselines in different projects can be valuable. For example, suppose you have a “catalog” project, consisting of standard requirements. A new project starts by including all the requirements in the catalog. A comparison of baselines in the two projects would now show no differences. As the project progresses, it replaces standard requirements with project-specific copies when the needs of the project diverge from the standard. A comparison of baselines in the two projects would now display exactly those copies and hence show how the project has diverged from the standard catalog.