Table A1.

Determinants of political group cohesion. (The dependent variable is the relative Rice index for a political group in a vote. Robust t-statistics in parentheses. ^*p≤0.05, ^**p≤0.01. Policy area variables (including economic, social, agricultural, institutional, internal and budgetary variables) are included in the estimations but their coefficients are not reported.)

	PES	EPP-ED	ELDR	UEN	G/EFA	EUL/NGL
majority size	−0.289	−0.367	−0.220	−0.375	−0.392	−0.372
	(15.63)**	(19.49)**	(14.15)**	(17.00)**	(24.28)**	(19.97)**
absolute majority	−0.014	0.030	−0.034	0.013	−0.006	0.018
	(1.69)	(3.11)**	(3.84)**	(1.14)	(0.79)	(2.03)*
final reading	0.012	0.031	0.017	0.007	0.014	0.016
	(1.10)	(2.64)**	(1.66)	(0.47)	(1.49)	(1.23)
whole bill	0.020	0.030	0.000	0.019	0.022	0.023
	(2.94)**	(4.30)**	(0.02)	(2.08)*	(3.36)**	(3.15)**
legislative	−0.080	−0.073	−0.007	0.042	0.030	−0.047
	(2.95)**	(1.90)	(0.22)	(0.91)	(0.65)	(0.86)
agenda setter	−0.005	−0.006	−0.009	−0.014	−0.002	0.015
	(0.99)	(0.99)	(1.28)	(0.40)	(0.20)	(1.35)
party calling RCV	0.017	0.012	0.003	0.017	0.007	0.012
	(2.12)*	(2.05)*	(0.44)	(1.24)	(1.41)	(1.46)
party is winner	−0.036	−0.027	0.005	0.028	−0.002	0.006
	(5.54)**	(4.01)**	(0.93)	(4.12)**	(0.39)	(1.15)
party is pivotal	0.098	0.043	0.181	0.176	0.232	0.227
	(17.11)**	(7.79)**	(26.16)**	(9.61)**	(38.71)**	(26.76)**
participation	−0.060	−0.067	−0.044	−0.142	−0.068	−0.080
	(4.07)**	(4.10)**	(3.13)**	(6.43)**	(4.84)**	(4.68)**
co−decision	0.056	0.037	−0.004	−0.025	−0.023	0.060
	(2.11)*	(0.97)	(0.14)	(0.55)	(0.49)	(1.10)
consultation	0.044	−0.001	−0.016	−0.030	−0.076	0.003
	(1.70)	(0.03)	(0.55)	(0.67)	(1.64)	(0.06)
constant	0.880	0.927	0.772	0.887	0.962	0.913
	(44.70)**	(45.74)**	(42.36)**	(33.90)**	(54.30)**	(42.88)**
observations	5163	5163	5160	5082	5159	5159
R-squared	0.20	0.14	0.27	0.10	0.35	0.25