This book has its genesis in a confluence of enticing circumstances: the existence of an important but puzzling phenomenon as old as parliamentary democracy itself, the development over time of a profusion of incompatible explanations for the phenomenon, and the recent emergence of a methodology holding out the promise of resolving the confusion. The phenomenon in question is the well-known tendency for government survival rates to vary enormously both within and across parliamentary systems. If one accepts that the length of time governments survive strongly affects their ability to govern effectively, then it follows that our understanding of parliamentary democracy depends very much on the explanation of this variation. Identifying the correct explanation, however, has not proved to be straightforward. It has often been assumed, to cite one major example, that unbridgeable ideological or policy differences among member parties constitute a prime source of coalition government collapses, yet a recent survey (Laver and Schofield 1990:155) finds no systematic evidence to support the claim. To add fuel to the fire, there appeared in the 1980s a major school of thought that asserted that government dissolutions are essentially random and therefore unamenable to causal analysis. Fortunately, the past few years have also seen the introduction of a statistical methodology, event history analysis, that is capable of reconciling causal and random approaches, and a good deal else as well.

Any methodology is only as good as the data to which it is applied.