What affects a count of reports
A count of reports counts reports. It does not count events, and it is not a rate. This guide gives what FDA says about the count. The site read the FDA pages on .
The site gives no reason of its own why a count is high or low. It repeats the reasons that FDA gives.
How many people use a product
Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. Many drug products appear frequently in adverse event reports simply because they are commonly taken by many people in the population, not because they are responsible for more adverse events.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
The openFDA files do not give the number of people who use a product. So no page of the site gives a rate.
Time on the market and publicity
Further, FDA does not receive reports for every adverse event or medication error that occurs with a product. Many factors can influence whether or not an event will be reported, such as the time a product has been marketed and publicity about an event.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
Voluntary reports and reports of manufacturers
Reporting of adverse events by healthcare professionals and consumers is voluntary in the United States. If a manufacturer receives an adverse event report, it is normally required to send the report to FDA.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
Some reports come directly from user facilities (like hospitals) or device importers (distributors), while others come directly from manufacturers.
Source: openFDA, Device Adverse Event Overview. The site read the page on .
Duplicate reports
There are many instances of duplicative reports and some reports do not contain all the necessary information.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of . The site read the page on .
The site does not remove duplicates. A count is not a count of events or of patients.
Why the total number of reports rises
In recent years the FDA has undertaken efforts to increase collection of adverse events. Increases in the total number of adverse events is likely caused by improved reporting.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
When FDA releases the data
Quarterly. However, please be advised that the data in this API may lag by 3 months or more at any given time, depending on when the quarterly FAERS data is released.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
MAUDE is updated monthly and the search page reflects the date of the most recent update.
Source: openFDA, Manufacturer and User Facility Device Experience. The site read the page on .
So the newest months of a chart are not complete. They grow in later releases.
What FDA says about device counts
MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices.
Source: openFDA, Manufacturer and User Facility Device Experience. The site read the page on .
See also What FAERS and MAUDE are.
Follow a count without making a rate
Lipitor appears in 55,172 reports received from 2004-01 to 2026-06.
The drug data ends on 30 Jun 2026. The device data ends on 30 Sep 2026. A later device cutoff does not extend the drug series.
The count has no denominator for people who used this medicine. Dividing it by all FDA reports would give a report share, not a reaction rate.
The record links its CSV beside the yearly table. Keep the received period and FDA caveat with the downloaded count.
Last checked against FDA pages: .