A Leadership Selection Index for multi-ballot political party conventions in Canada

Eugene McGregor (Journal of Politics 35, 459–478, 1973) recognized a regularity in multi-ballot leadership conventions in the United States. He hypothesized that the change in absolute votes between the first and the second ballot could be used to forecast the eventual winner of a leadership race. When the McGregor model is applied to the Canadian multi-ballot conventions the prediction rate is only 57 per cent. This paper seeks first to discuss the qualitative similarities found between these Canadian conventions and then use this as a basis to develop and to apply a model that extends on McGregor's work. The developed model is called the Leadership Selection Index (LSI). We find that the winner of most Canadian multi-ballot conventions (86%) could be forecasted after the second ballot by using the LSI method of analysis. Based on the evidence from the literature and a survey of Canadian political conventions, we develop a hypothesis of ‘two critical conjunctures' for multi-ballot leadership conventions. This hypothesis provides a suitable theoretical framework to interpret the performance of our empirical model.