“…Though it is recognized that these non-institutional mechanisms do play a role, it is also argued that they are difficult to measure over 304 regions. Factors which might hinder or increase regional involvement, such as party political (in)congruence between the centre and its regions (Bauer, 2006: 34),7 pan-European regional networks and associations (Tatham, 2008: 508–509), the entrepreneurship of regional representatives (Jeffery, 2000: 14–16), personal chemistries and networks between state and regional élites, the role of issue saliency (Blatter et al ., 2008: 467; Tatham, 2008: 503), the compatibility of policy preference constellations, the embeddedness of regional executives in networks of private and public actors (Fargion et al ., 2006: 770–771), perceived legitimacy and social capital (Jeffery, 2000: 17), or socio-historical and cultural factors (Soldatos, 1990: 44–46), had to be excluded. Though often relevant, their occurrence and effect over 304 regions are either intractable or unsystematic.…”