IMF statistics are widely used when proving a point in journalism, academic research or any other type of report. There are a handful of sources to turn when you need a legitimate source and the IMF's wonderful website is one of them.
It's full of statistics, economic research, news and pages dedicated to just explaining to you what the heck the IMF does... sounds like a exhilarating experience no?
There is already a raging debate among academics, economists and politicians if the good produced by the IMF outweighs the bad.
You don't see IMF economists, moving markets with their speeches on major news networks.
This is because they don't and they can't. When it comes down to it the IMF has true little power to influence momentum in markets. Financial markets don't care about what the chief economist at the IMF thinks or says because anyone in the business probably has a research department in their company that has already come to the same conclusion. Heck, I could have Googled what these IMF guys said in this Reuters video.