Irina Stefuriuc, "Government Formation in Multi-Level Settings: Spanish Regional Coalitions and the Quest for Vertical Congruence," Party Politics, 15 (January, 2009), 93-115..

First paragraph:
Coalition formation is one of the main challenges that political parties face in decentralized political systems. Still, it has received surprisingly little attention from scholars of party politics in multi-level settings. In unitary systems, coalition formation can be a complex game, yet the determinants of coalition formation at the national level belong mostly to the same level of party action. National-level governments generally respond to national-level stimuli, such as parliamentary and party system characteristics, party organizational features and, more generally, the structure of national electoral competition

Figures and Tables:

Table 1. Congruence of government composition across levels

Figure 1. Two-dimensional ideological positioning in Catalonia, 2003

Figure 2. Two-dimensional ideological positioning in the Canary Islands, 2005

Figure 3. Two-dimensional ideological positioning in the Basque Country, 2005

Figure 4. Two-dimensional ideological positioning in Galicia, 2005

Last Paragraph:
Nevertheless, this article shows clearly that congruence is an important variable for coalition formation in multi-level systems. It also shows that a coalition theory that ignores institutional effects and party attributes, or fails to account for possible differences in party goals at different levels, is not going to take us very far in explaining government formation in such settings. That is why we should be cautious before simply testing quantitatively classical coalition models with regional-level data, but rather should supplement this by a qualitative analysis of party strategy.