Let's say it turns out that USAID spent a lot of money on IFPRI and only a small percent of it went to fund this little site, which is indeed quite likely. Does that then imply that the other [large percent] was therefore well spent? Or even probably well spent?
No, but it does prove the existence of such corruption and waste which is suggestive of more. And the problem is that a lot of this stuff is near impossible to sort out at scale. For instance the Red Cross spent $1.5 billion in donations 'rebuilding' after the Haiti earthquakes, to ultimately build a total of 6 permanent dwellings. [1]
Obviously everything was not even remotely on the up and up there (and appropriately enough, USAID was also involved), yet nothing was ever proven and no consequences were ever suffered even in an extremely high profile incident like this.
So the only solution here is to ensure any spending is competently scrutinized and overseen from the get go. But these numerous incidents of waste and corruption show that simply wasn't happening.
[1] - https://www.propublica.org/article/how-the-red-cross-raised-...