For those of you who are interested in having the highest CP evolutions, here is the IV Rater calculator you need to know / understand.
https://thesilphroad.com/research
In short, plug in the data and find out the IV % for CP, this will tell you if the base Pokemon is good for the evolution to the next stage (or two), or if you can find / hatch a better one. Anything 85% and higher is solid, 90% and up is what you're looking for.
Real life example: I found a 613CP Squirtle in the wild with some room to grow (ended up being 675 after powering up). Thought this would be the perfect Squirtle to evolve into Blastoise. My friend had hatched a 577 Squirtle from an egg. Obviously, we thought my Squirtle was the better of the two. However, after evolving to Blastoise, mine ended up 1743CP and his at 1910CP! We are the exact same level. Come to find out, when plugging in my Squirtle into the IV Rater calculator, it was only a 60%. His was 91%. It's a hidden stat that combines many variables and is absolutely a good way to find out if your base Pokemon is the one you want to power up and evolve. Learn from my mistake lol.
**it's been rumored (and seems like it's true) that the best IV Pokemon come from hatched eggs as opposed to being found in the wild. So don't assume that just because you have a higher CP Pokemon that one below it is inferior - absolutely may not be the case.