This appendix examines the impact of demotion on an MP's parliamentary career. I estimate a model of ministerial career prospects with data from the 1972 cohort of Canadian Liberal and Conservative MPs. The sampling frame spans 1972 to 1995, the year by which the last MP elected in 1972 left the Commons. The dependent variable is a dummy variable that notes whether an MP enjoyed some time as a junior or senior minister or opposition critic. The key independent variable is a demotion variable that measures the number of ranks (if any) that an MP was demoted during their career. (If MPs were demoted twice, the data were based on their careers up until that first demotion.)

MacDonald's (1987) work on parliamentary careers stressed that MPs' professional ambition was the single best predictor of upward mobility, and it is quite reasonable to imagine that ambitious MPs are more likely to shrug off a setback and start a second climb up the parliamentary career ladder than their less ambitious colleagues. If ambition is a critical control variable, it is also a difficult one to measure. MacDonald used surveys to assess how professionally ambitious British MPs were, but I do not have the luxury of these sorts of data. Instead, I use the MP's career trajectory to construct a proxy for ambition.