Françoise Boucek, "Rethinking Factionalism: Typologies, Intra-Party Dynamics and Three Faces of Factionalism," Party Politics, 15 (July, 2009), 455-485.

First paragraph:
Political parties are not monolithic structures but collective entities in which competition, divided opinions and dissent create internal pressures. In turn, these pressures often trigger the formation of factions that render the unitary actor assumption highly questionable. Although widespread, factionalism is still a relatively under-studied phenomenon. In political science, the analysis tends to vary from extremely quantitative to purely intuitive, and crossnational surveys are few. The dominant approach to the study of factionalism as an independent variable has been to devise typologies based on subparty group categories with different features. However, this analytical approach has turned out to be a bit of a minefield.

Figures and Tables:

Table 1. Summary of key studies of factionalism in political science

Figure 1. Mapping out and labelling factions

Table 2. Three faces of factionalism

First Paragraph of Conclusions:
Following a review and critique of the study of factionalism in political science, I have suggested in this article that conceptualizing factionalism through categories of different types of intra-party groups is problematic because underlying variables with which to characterize factions are difficult to dissociate and often turn out to be interactive. Consequently, I suggest that it is preferable to take a non-exclusive view of factionalism and to focus attention on group dynamics. Factionalism should be seen as a general process of subgroup partitioning and it is the nature of this process which gives factions their specific characteristics. This means that factions characterized differently under traditional schemes (for instance, ideological factions versus factions of interest) can act similarly - cooperate or compete - and that factions characterized in the same way can act differently. For instance, factions of interest can be cooperative (as illustrated by the district-level electoral cooperation of LDP factions), but also competitive (as rivals in the selection of party leaders and policy programmes and in the distribution of 'pork') as well as degenerative (if incentives are excessively privatized). However, there is nothing predetermined about these processes and, through institutional reforms or astute leadership, it is possible for party factions to move from a mode of intra-party competition to one of cooperation.