Is education what it takes to be a credible journalist?

Many journalists these days are not educated, and the rest typically have a degree. Some people say that it is possible to educate yourself through youtube and sites such as that. Which yes it is, but many people spend so much money on an education through a credited school and sometimes it isnt even worth it. What I mean by worth it is, if school is not what people look for when wanting to know if a journalist is credible, than what was the point of you going to school for four years and acquiring an education. Even if school is not the fact at hand. What I want to know is when you are selecting a journalist, how can you tell if they are credible? Do you look at their past jobs, or their education history, or even look up recommendations? So saying that school is not the main matter, what can you go off of. I do understand that word of mouth is very important, but I feel that when trying to search for someones credibility, school and education is very very important, and can help count for a large amount of credibility. Basically all I am trying to get at is that many students go to school and spend a lot of money on an education, and when it comes down to a job a lot of times someone without an education is employed as well. So if it is a journalist, I want to know what counts as a form of credibility for them if they do not have an education?