Eric McLaughlin, "Electoral regimes and party-switching Floor-crossing in South Africa's local legislatures," Party Politics 18 (July, 2012), 563-579. [Available at http://ppq.sagepub.com/content/vol18/issue4/ ]

First paragraph:
When legislators are elected under the banner of one political party and, between elections, decide to switch parties, it raises interesting questions about representative democracy and its core institutions. There have been many studies of the correlates and consequences of this behaviour in the United States, where, compared to many other democracies, it is quite rare (Grose and Yoshinaka, 2003; McCarty et al., 2003; Nokken, 2000). Studies examining party-switching in contexts outside the United States have produced insights about why and when legislators switch parties as well as what they gain by doing so. Even so, the number of comparative studies on party-switching remains small and analysis of party-switching remains an insufficiently exploited opportunity in the study of comparative party politics.

Figures and Tables:

Table 1. Direction of Defections in the 161 Local Legislators Included in the Dataset

Table 2. Electoral Regimes and Defection in 2002/4 Dependent Variable: Did Legislator Defect?

Table 3. Predictors of Defection for Smdp Legislators in 2002/4

Last Paragraph:
(first paragraph of conclusions) This study advances our understanding of party-switching on several fronts. First, the article provides insight into the logic of party defection in South Africa, a case where patterns of defection were broad. At first glance, most party-switching in South Africa appears to be easily explained by a narrative about an alliance break-up and a set of politically opportunistic floor-crossing laws spearheaded by the ANC. The evidence presented here shows that defection activity was more complex than the aggregate data might indicate. While a broader political narrative may account for the emergence of party-switching, the nuances of the pattern itself conformed very much to the logic of what Desposato has called the 'highly structured, rational, and constrained' market of 'parties for rent' (2006). All legislators were influenced by factors such as the size of the largest party, their position vis-a`-vis the largest party and whether the law required them to make their moves with co-defectors or allowed them to go it alone. The size of the largest party in a legislature and,more broadly, the relationship between the sizes of all major parties in a legislature and the importance of certain size thresholds, have emerged in several recent studies as explanatory variables (Kato and Yamamoto, 2009; Laver and Benoit, 2003). This study confirms these earlier results. In particular, it provides suggestive evidence that it is, as Kato and Yamamoto (2009) suggest, important to consider how the environments within which legislators operate create uncertainty about the future and how legislators may use defection as a strategy for coping with this uncertainty. At their core, parties in legislatures and those who seek membership in themlive by the logic of thresholds even when they speak in the language of ideas.