How to calculate attack roll for a monster?

Question

I'm a total Pathfinder newb and I have a question that will probably reveal just how "newb" I am.

According to the Core Rulebook, to calculate an attack roll, you use the following formula:

d20 + attack bonus

For melee attacks, your attack bonus is calculated as follows:

Base attack bonus + strength modifier + size modifier

With this in mind, consider the humble goblin, found here:

http://www.d20pfsrd.com/bestiary/monster-listings/humanoids/goblin

Let's say the GM is going to make a melee attack roll for this creature, versus a PC. Does he add +1 for the small size, another +1 because of its Base Attack Bonus, plus the strength modifier (0, in this case) and then add the +2 listed for the short sword melee attack?

Or does he simply add the +2 for the short sword melee attack, as if all the other factors were rolled into this number?

Answer 1

He just uses the +2 for the short sword melee attack. That site has already calculated the attack bonus. As you calculated, the goblin is getting is +1 from BAB, +0 from STR, and +1 from size, for a total attack bonus of +2.

For comparison, note that he has a +4 with his shortbow: +1 from BAB, +2 from DEX, and +1 from size. (You use dexterity rather than strength for ranged attacks.)

slang definitions: BAB = base attack bonus, STR = strength, DEX = dexterity