Something that can't be measured or compared, is social confidence (for lack of a better term). This is really on my radar because I was a fairly shy kid, who became a horribly shy and anxious pre-teen. I always knew I wanted to do everything I could to enable my children to be as outgoing as they could be and have the confidence to be who they really are.
I just love watching Everly now when we go out and about. She is incredibly outgoing and charismatic (she takes after her Dad!). She seems to be able to win adults and children over in minutes. We have a 4 year old who lives across the path from us. We live in a townhouse where all the cars are parked underground. Everly and A have become best friends. When I watch them play and interact together it just amazes me how much Everly keeps up with her friend. Not in terms of what she knows, but in terms of how to interact with another person.
She might not be able to recite her ABC's and 123's, or know all her colours... but watching her with other people reminds me that there is so much more to learn than just "school skills".