Get the data from MANY sources that theoretically have no ax to grind (government agencieS, universitieS, scientific associationS, etc.). Then make up your own mind. You can learn a lot in the process as you strive to understand what you're being told. For example, in researching a fairy tale I discovered that Little Hawk had originally been a frog, but after the Princess looked at what had come from her kiss (besides lip warts) she ran away screaming.

Seriously, use as many sources as you can, whether or not they support your original thesis. Then change your mind if the data shows you're wrong. (People live longer who can change their minds.)