Gamma World 7e: Clarification on Mutant powers attack values

Question

Our group realized we had a confusion on how mutant powers really work. Do we use the actual stat value or the stat bonus?

Here is an example (almost all powers are like this):

Page 37 - Cockroach - Eau De Roach - "Attack: Constitution + your level vs. Fortitude"

My character is level 4 and has Constitution : 18 (+4)

So which is true:

1. my attack roll is 18 (Constitution value) + 4 (Level)= 22 + 1d20, or

2. my attack roll is 4 (Constitution bonus) + 4 (Level) = 8 + 1d20?

Answer 1

Use the stat bonus

Assuming you have an 18 (+4) constitution and are level 4, a constitution-based attack would be 1d20+8 for the attack roll.

From the core Gamma World book, page 17 (emphasis mine):

Attack Rolls: ... Roll a d20 and add your attack modifier (your level + your ability modifier) for the attack. ...

To my knowledge, your hit point total is the only place you ever use the stat value (called an ability score) rather than the stat bonus (called an ability modifier). The ability scores are there because they do additional things in Dungeons & Dragons, which Gamma World is based on.