To report this story, ProPublica and the Pittsburgh Post-Gazette analyzed a database of more than 17 million complaints about medical device malfunctions, patient injuries and deaths submitted to the U.S. Food and Drug Administration’s Manufacturer and User Facility Device Experience, or MAUDE, tracking system. Because the FDA system is cumbersome and difficult to navigate, the news organizations paid for a subscription to a proprietary database of MAUDE reports called Device Events, developed by former FDA analyst Madris Kinard.

Reporters used these government records to better understand the reporting practices of Philips Respironics and more than two dozen other large medical device manufacturers. The records showed how often companies, including Philips, submitted timely reports about potentially dangerous devices to the government and how often the reports were late.

During this analysis, reporters discovered that the FDA directs device makers to update the dates they first became aware of a defect when submitting follow-up information to the government. The new dates are put into the agency’s public tracking system, overriding original dates and obscuring how long companies had the warnings in hand before turning them over to the government.

In a first-of-its-kind analysis, reporters compared the dates on file in the government’s public tracking system to the dates on the original reports, which were maintained by Device Events. In all, the news organizations compared the dates on more than 100,000 reports from more than two dozen companies dating back to 2013.

Students at Northwestern University’s Medill Investigative Lab helped read and sort hundreds of the reports.

To better understand the FDA’s ability to monitor its tracking system and respond to problem devices, the reporting team interviewed current and former FDA administrators, quality assurance experts for medical device companies as well as public health practitioners who have studied and written about the agency. Over the course of the investigation, the team also examined years of FDA warning letters, inspections, recall notices and safety alerts along with Department of Justice consent decrees and criminal filings.