A medical bill emailed to Vox senior policy correspondent Sarah Kliff got her interested in emergency room facility fees—a widely applied, highly variable, and little understood cost in the healthcare system. The fees, set between hospitals and insurers, are the charge from the hospital for coming in for treatment.

Last October, Kliff set out to learn more about these fees through one of the only ways she could think of to get the information: by collecting hospital bills.

By putting out calls on social media and on the site, Vox amassed a collection of emergency room bills. Kliff worked with Senior Engagement Manager Lauren Katz, News App Developer Kavya Sukumar, Visuals Editor Kainaz Amaria and Special Projects Editor Susannah Locke to get the project off the ground. Today, the database comprises more than 1,600 bills from every state and Washington, DC. So far, Kliff has written half a dozen articles from the database, and she’ll continue the to report from the trove through the end of the year. Since Kliff started the project, lawmakers have introduced multiple bills to address surprise medical fees, including legislation sponsored by New Hampshire democratic Senator Maggie Hassan that aides told CJR is inspired by Kliff’s reporting.

CJR spoke with Kliff about how she came up with this approach to researching murky healthcare pricing, what her reporting has accomplished, and what other journalists can learn from her experience. This conversation has been edited for length and clarity.

How long have you been covering healthcare and how did you get interested in this beat?

I started covering healthcare almost a decade ago. I first started with the Affordable Care Act. I was in an entry level position at Newsweek, [where I covered] the consumer health department, and then was on politics. They needed someone to write about the healthcare fight that was happening in Congress. I raised my hand for it, and that’s what I’ve been doing ever since.