In short, the information in IMDb comes from various sources!
While we actively gather information from and verify items with studios and filmmakers, the bulk of our information is submitted by people in the industry and visitors like you!
In addition to using as many sources as we can, our data goes through consistency checks to ensure it's as accurate and reliable as possible. However, there's absolutely no substitute for an international team of entertainment fans with an encyclopedic knowledge of trivia and a large assortment of reference works (and we include in this group many of our loyal contributors).
Our sources of information include, but are not limited to:
Given the sheer volume and the nature of the information we list, occasional mistakes are inevitable and, when spotted/reported, they are promptly verified and fixed. That's why we welcome corrections and submissions. Our service is provided for the information of users only.