Campaign contributions to state-level candidates for office, state-level ballot measures, and all state-level recipient committees can be quickly and easily browsed using MapLight's California Power Search, a tool developed in partnership with the California Secretary of State that utilizes the Secretary of State's bulk data download, displaying data from 2001 through the present.

Our database also includes campaign contributions given to each member of the 2009-2010, 2011-2012, and 2013-2014 California State Legislatures since January 1, 2003. We include all contributions by donors giving $100 or more to one candidate. This data is obtained from the National Institute on Money in State Politics (NIMSP), which "cleans it up" to make it more useful for analysis. NIMSP standardizes contributor names and categorizes each contribution according to the interest group of the donor.

Interest Group categories

NIMSP categorizes each contribution according to the industry of the donor, using a taxonomy of the 400-odd interests that give money to politics. For example, contributions from the Hollywood Park Casino and personal contributions from Curren Price, Vice President of that casino, are both tagged as "Casinos, racetracks, & gambling." On our site we call these categories "interest groups" or "interests." 

This interest-group categorization allows research on overall trends, such as patterns of contributions from oil interests. On the MapLight site you can view individual contributions—who gave what to whom, on what date—or you can view contributions aggregated by interest group.

These interest group categories make up a three-level hierarchy, with some interest groups being part of others. For example, the interest group category Petroleum refining & marketing is part of the larger category Oil & Gas, which is part of the still larger category Energy & Natural Resources. This hierarchical system makes it possible to examine both specific industries and larger trends.