Democracy Country Ratings (Gastil index of Democracy), with wide coverage of countries, from http://www.freedomhouse.org/. It is broken down
in: political rights, civil liberties, and freedom status, 1972-2000
“Database of Political Institutions”, Beck et al: it has a variety of data for a large number of countries, 1975-1997. It includes more than 100 variables regarding the chief party in power, major opposition parties, legislature, checks and balances, electoral rules, federalism.
ICRG data: data on corruption with the following variables: Socioeconomic Conditions, Investment Profile, Government
Stability, Rescaled External, Conflict Risk (0-10), Corruption [0,6], Military in Politics, Religion in politics, Law and Order Tradition, Ethnic Tensions, Democratic Accountability, Quality of Bureaucracy. Data for a large number of developed and developing countries, for the years 1984-1999. Monthly and yearly data available. For information on how data are collected, see http://www.prsgroup.com/icrg/icrg.html(it
is the site of the company that collects and sells these data).
The following papers contain useful frameworks and data:
Persson, Torsten, Guido Tabellini and Francesco Trebbi, , “Electoral rules and corruption” CEPR Discussion Paper No.2741.
Persson, Torsten, Guido Tabellini, “Political Institutions and Policy Outcomes: What are the Stylized Facts?”
(other papers on this line by Persson and Tabellini and relative datasets available at: http://www.iies.su.se/~perssont/workpap.htm)
Triesman, Daniel, , “The Causes of Corruption: A Cross National Study,” Journal of Public Economics, 76, 399-457.
Kaufmann, Daniel, Aart Kray and Pablo Zoido-Lobaton , “Aggregating Governance Indicators”, World Bank Policy Research Department Working Paper No. 2195.
La Porta, Rafael, Florencio Lopez-de-Silanes, Andrei Shleifer and Robert Vishny, , “Law and Finance,” Journal of Political Economy, 106(6), 11113-1150.
La Porta, Rafael, Florencio Lopez-de-Silanes, Andrei Shleifer and Robert Vishny, , “The Quality of Government,” Journal of Law, Economics and Organization, 15(3), 222-279.