In the NDepend Project Properties > Analysis > Baseline for Comparison > History Analysis Results, the user can choose where History Analysis Results are stored and the frequency of storage.These results can then be used as baseline.

It might happen that some History Analysis Results are lacking some important data, like coverage data or some specific source code data, because at analysis time this info was not available.

When such result is chosen as baseline, this has an important impact on issues computed and on the technical debt estimated. For now the user can remove concerned History Analysis Result by removing related folders as explained here:

http://www.ndepend.com/docs/technical-debt#NoCoverageDataOnBaseline

If you'd like us to provide a UI that would list History Analysis Results, that would show which ones doesn't have coverage data (or others flaws like source code not resolved), and that would let remove them, please vote for this feature.

We could also provide a filter at analysis time that would not persist an analysis result as history if it doesn't satisfy certain criteria (like coverage data available...).