: Total exports and imports of goods and services as percentage of GDP. Source:
OECD, National Accounts, Part II: Detailed Tables (various years).
Left government center of gravity. This is an index of the partisan left-right “center of gravity”
developed by Cusack (1997). It is based on (i) Castles and Mair’s (1984) codings of government
parties’ placement on a left-right scale, weighted by (ii) their decimal share of cabinet portfolios.
The index varies from 0 (extreme right) to 4 (extreme left), although most observations are much
closer to the mean. The data was generously made available by Thomas Cusack.
Concentration of union power. This variable is the product of union density and the centralization
of union power in wage bargaining. Density is measured as the number of union members relative
to the labor force, while centralization is measured by a time-sensitive index of centralization of
wage bargaining. Sources: Visser (1989; 1996); Iversen (1998).
Electoral participation . The data is based on voter turnout rates as recorded on an annual basis in
Mackie and Rose (1991) and in the European Journal of Political Research .