How Reliable are the Data

Question

I am trying to search data with the drug name Hydroxychloroquine from the URL here from OpenFDA API

https://api.fda.gov/drug/event.json?search=patient.drug.medicinalproduct:%22chloroquine%22+AND+receivedate:%5B20200101+TO+20200513%5D&skip=1&limit=2

There are 2918 relative results, but I found that only 2637 (2207 are male, 430 are female, 0 are unknown) patients with 'patientsex' feature. Could I know why does that happen? Will some results repeated or a supplemental of a result that has already existed in the database?

Answer 1

Reporting a patient's sex is voluntary, which is why some adverse event records do not have that information.