In simpler times, when donors were donors and PACs were PACs, campaign spending was easy to follow. A review of a politician’s campaign donations—recorded by the same agency in the same place—would provide the lowdown on all of his or her biggest backers.

But in the brave new world of campaign finance, this basic question has become more complicated. Citizens United and related Supreme Court decisions have given rise to super PACs and political “social welfare” groups, entities that spend unlimited amounts on elections with varying degrees of disclosure.

Campaign 2012 is now over, obviously. But as a new Congress begins its session and the last bits of campaign finance data from late last year become available, journalists around the country have another opportunity to introduce their audiences to the donors and special interests that helped put their elected representatives in office.

To provide a complete picture of who is bankrolling elections, though, reporters and citizens now must consider a broader landscape. They need to review records of different types, kept in different places. There is currently no single, easy-to-use source where all campaign spending on behalf of a candidate is gathered in one place.

This primer offers a beginners’ guide (and a review for more experienced journalists and advocates) on how to fully examine a politician’s campaign funding. Watchdog organizations that promote transparency and have done essential work in making campaign finance data readily accessible, such as the Center for Responsive Politics and the Sunlight Foundation, could help facilitate this process by providing a resource that puts all of a candidate’s funding in a single place. Until then, the steps detailed below explain how to examine and disclose the campaign money—both traditional donations and outside spending—behind a candidate for federal office:

1) The Traditional Money

Most of the money that goes into federal races still comes from traditional donors: individuals and PACs that contribute directly to politicians, and must disclose their contribution to the Federal Election Commission (FEC). An individual can give up to $2,500; PACs and party committees can give up to $5,000 per campaign. Individual contributors are also required to disclose their employers and professions, information that shows which companies and industries are a candidate’s biggest backers.

The website, run by the Center for Responsive Politics, offers one of the best summaries of a candidates’ traditional donations. When you select a politician, the tabs near the top of the screen also offer breakdowns of these donations by election cycle, biggest donors, top contributing industries and sectors, and more.

To illustrate the process, we’ll examine who is bankrolling Tim Bishop, a Democrat from Long Island who was narrowly re-elected in 2012 after a nasty and expensive race against Republican Randy Altschuler. Records show that Bishop raised $2.7 million in traditional donations in the race, receiving his greatest support from retired people, leadership PACs of fellow Democratic office holders, and lawyers and law firms.

PAC contributions to Bishop over time illustrate a pattern that is common among long-serving Democrats. When Bishop was first elected in 2002, the PACs that provided his greatest support were labor and ideological groups, with negligible support from business PACs. Over time, this balance has shifted, and in the 2012 cycle Bishop received more traditional donations from business PACs than from labor and ideological committees combined. Examining how politicians’ donor bases change over time—such as the proportions of campaign cash coming from local vs. national groups, or issue advocates vs. Wall Street and other business interests—can suggest avenues for further reporting about whether time in Washington is changing their priorities.

2) Independent Expenditures

Most outside spending—and almost all outside spending that can be tracked—is made through so-called independent expenditures. These are political communications that specifically call for the election or defeat of a candidate, and must not be coordinated with any candidate’s campaign. There are no limits on how much an individual or group can spend in this way, and spending by super PACs and some spending by political nonprofits falls into this category. Like traditional donations, independent expenditures must be reported to the FEC.

Sasha Chavkin covers political money and influence for CJR's United States Project, our politics and policy desk. He has written for ProPublica, the Center for Public Integrity, and The New York World. Follow him on Twitter @sashachavkin.