Recently, The Ballot Book launched our campaign finance platform — the most sophisticated and user-friendly way to access campaign finance data for California state committees and elections. It allows users to easily identify who is spending money, and on which candidates.

Thanks to this new platform, we’re now able to explore virtually endless dimensions of California campaign finance and its potential impact on legislation and policy.

One of the first questions we set out to answer was: which committees have been the shrewdest at backing winning candidates — and by extension, increasing their influence over the legislative process?

To find out, we analyzed the last three election cycles (2020, 2022, 2024), focusing specifically on statewide primary and general elections for State Assembly and State Senate.

While any group can support a candidate who eventually wins, it’s far more revealing when they back that candidate early, before the outcome is clear. To measure this, we looked at contributions made to candidate committees before the primary election. Any such contribution — regardless of amount — was treated as an “endorsement.”

After all, organizations rarely write checks without first endorsing a candidate. Contributions are a strong signal of support.

We then examined how many of those candidates went on to win in the general election and ultimately become legislators.

We approached this in two ways. First, we looked at each committee’s overall performance across all races. However, those numbers can be skewed by the presence of incumbents — who tend to have a much higher chance of reelection and represent a safer bet.

To account for that, we also analyzed open-seat races where no incumbent was running, offering a clearer picture of which organizations are willing to make strategic, higher-risk endorsements.

Each table below shows how many “winners” each of the top 50 committees had, how many total candidates they endorsed before the primary, and their resulting “hit rate.” It’s one thing to endorse broadly; it’s another to consistently pick winners. The final column shows how much money each committee contributed in these early endorsements — offering a sense of not just accuracy, but financial weight.

What the Data Shows

To view the results, scroll down to the two tables below. If you’d like to explore the data further, you can also download the raw Excel files for both tables at the end of this post.

In both categories — overall candidates and open-seat races — the organization with the most winning endorsements was the California Professional Firefighters Political Action Committee. They backed 223 winning candidates overall, including 90 in open-seat contests.

When it comes to hit rate, the Cooperative of American Physicians State Political Action Committee had the highest success rate among all candidates. However, they made just 94 endorsements — fewer than most other organizations on the list.

In the open-seat category, the California Defense Counsel Political Action Committee posted an impressive 83.7% success rate, but they only weighed in on 43 races — again, on the lower end in terms of volume.

So, which metric matters more? You could argue that racking up the most winning endorsements — and thus cultivating the largest bloc of allied legislators — is the most important measure of political influence. But you could also argue that precision and efficient resource allocation, reflected in hit rate, are just as meaningful.

This also raises a broader question: are these committees actively shaping outcomes through their endorsements, or are they simply skilled at identifying likely winners and backing them early? That’s a more complex dynamic — and one we may tackle in a future post.

For now, explore the data below. And if this kind of campaign finance analysis interests you, consider subscribing to our platform — the most comprehensive source for California election and campaign finance data.

Top Committees Among All Candidates

Top Committees Among Open Seats