In particular, they also list where your money is going, so you can just pick and choose which of their causes you want to support (although I personally donate directly to them so they can decide which charity they think currently maximizes impact-per-dollar): https://www.givewell.org/charities/top-charities
> I'd just encourage people to take 5 minutes and choose their own charities instead of blindly choosing their suggestions.
The problem here is that some organizations have a very well proven track record of solving real problems; some organizations instead focus on very nebulous "social messaging and awareness"; and some organizations exist primarily to pay their executives well.
A quick 5 minute search won't really yield a lot of information on effectiveness, but an organization like GiveWell can afford to hire actual researchers to answer these questions.
(I'm sure there's other decent sources to help evaluate that question, of course. GiveWell is just the one I'm most familiar/fond of)