Mark P. Jones and Scott Mainwaring, "The Nationalization of Parties and Party Systems: An Empirical Measure and an Application to the Americas," Party Politics, 9 (March 2003), 139-166.

First Paragraph:
We address an under-analysed issue in the comparative study of parties and party systems: their degree of nationalization. In the massive literature on party systems, considerable attention has been paid to the extent of polarization (Knutsen, 1998; Sani and Sartori, 1983; Sartori, 1976), the number of parties (Lijphart, 1994; Sartori, 1976; Taagepera and Shugart, 1989) and the level of institutionalization (Harmel and Svasand, 1993; Janda, 1980; Mainwaring and Scully, 1995). With the exception of some work on the United States, very little has been written on the degree of nationalization.

Figures and Tables:
Table 1: Political institutions in 17 countries (as of the most recent election)
Table 2: Party system nationalization in 17 countries, 1979-2001: PSNS, election year and period average
Table 3: Measures of stability in party system nationalization
Table 4: Party nationalization (PNS) in the low nationalization countries
Table 5: Ranking of the 11 most nationalized and least nationalized major parties
Table 6: Party nationalization (PNS) in the intermediate ntionalization countrries
Table 7: Party nationalization (PNS) in the high nationalization countries
Appendix: Using the Gini coefficient to measure party nationalization

Last Paragraph:
[These are the first two paragraphs of the Conclusion.]

The extent of party and party system nationalization is an important topic that has been neglected by the scholarly literature, except for the United States. This is in part because the mainstream theoretical literature on parties and party systems has focused on the advanced industrial democracies, which with a few exceptions have fairly nationalized party systems. But when we turn our attention to Africa, Asia and Latin America, a much greater proportion of the party systems are weakly nationalized. Hence, the importance of analysing variance in nationalization is greater for these regions than for the advanced industrial democracies. It is impossible to understand many party systems in the world, including those of such large and important countries as Argentina, Brazil, Canada, India and Russia without paying attention to the widely divergent vote shares that parties win in different states or provinces.

We have proposed a means of measuring nationalization that travels well across parties, countries and time. This article is the first to provide empirical information about party system nationalization outside of the advanced industrial democracies. Our work makes clear that party system nationalization varies markedly across countries.