Erik Voeten applies a study on civil wars and foreign intervention to Libya:
Stephen Walt points us to this working paper (ungated) by Duke University's Alexander Downes, who examines whether foreign imposed regime changes increase the likelihood of civil war. Downes finds that the answer is a clear "yes" if the purpose of the foreign intervention is to install a new leader in power as opposed to restoring a recently overthrown leader.
The likelihood of civil war is especially strong in poor and/or ethnically heterogeneous countries and if the regime change occurs in conjunction with defeat in an interstate war. Downes uses matching to deal with the obvious problem that foreign countries are most likely to intervene in cases that are violent to begin with (matching tries to create balance between a "treatment" group and a "control" group based on observed characteristics such as geographic location, democracy, and development. Matching does not control for unobserved differences that may make civil war more likely in countries where foreigners intervene).