I just got RB 2nd Ed and have not played yet. When you increase a combat ability with experience, does the bonus count on both the attack and damage value, or just the attack? Say I have a character with melee 2/1 and I purchase a +2 melee with experience points. Does the +2 effectively change my melee stat to 4/3? Thanks

Just the attack value upgrades, not the damage amount.

Enjoy the game!

Torbal is correct. I might add that if you are looking to increase damage, you'll want to do it via purchasing weapon items that have that feature.

Often times your choice of which stat to boost is affected by the items you acquire. For example, if there aren't any items that boost range damage but there are items that boost melee and you have a character who has a high range value to start, you may want to consider boosting melee.