Opposed Rolls

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Before going into a post likely to be snored off, I wanted to thank Kevin Sullivan for the stats he generated on this site. The presentation of certain things are more clear there. He also provided me with a good idea on how to generate Class XP tables for Andras.

I had posted on Google Plus about a shortcut method of performing opposed rolls. The numbers do not come out the same, but I figured that they were close enough. What I discovered in studying these numbers points to effects of specific designs. In the end, I think that my design doesn't produce results that are always similar, but that produces results more in line with my design philosophy.

Specifically, the results show that:

  • Characters with equal bonuses to skill rolls under Microlite20 will have a similar, but varied chances of success under my system.
  • The Microlite20 system is affected by relative adjustments to the roll. My system is affected by the actual skill ranks and Attribute score.

Here is an example using the Microlite20 rules as written and comparing to my system.

Listen is Subterfuge + MIND.
Move Silently is Subterfuge + DEX

Aesir is attempting to sneak up on a guard. Aesir has a 16 DEX and a Subterfuge rank of 2. The Guard has a MIND of 12 and a Subterfuge rank of 4. According to the rules, the one with the highest roll wins. Each character receives a bonus to their individual rolls of Skill Rank + Attribute Bonus.

For Aesir, we get 2 (skill rank) plus 3 (Attribute Bonus in M20) to get 5.
For the guard, we get 4 (skill rank) plus 1 (Attribute Bonus in M20) to get 5.

Given these stats, Aesir will succeed 47.5% of the time. The guard will succeed 52.5% of the time because he will win all ties. By rule, ties go to the character with the highest skill rank.

Under the Microlite20 system, the chances of success will not change if the guard has a Skill Rank of 5 and a MIND of 10, a Skill Rank of 3 and a MIND of 14 or a Skill Rank of 2 and a MIND of 16. The adjustment to the roll remains +5.

In my system, success is determined by rolling-under the total of the Skill Rank and the Attribute itself. When performing an opposed roll, the Player Character has to subtract half the total of the NPC's skill rank and attribute. In this example, Aesir's Subterfuge rank plus DEX is 18. The guard's Subterfuge rank plus MIND is 16. Success is determined by Aesir rolling equal to or under 10. In other words, 18 minus 8 (half of 16). This give Aesir a 50% chance of succeeding. This is a slightly better chance of succeeding than with the Microlite20 system.

What I found surprising is that if the guard is changed as I mentioned earlier, Aesir's chances of success are affected.

sub MIND Aesir Wins
Guard 1 5 10 52.50%
Guard 2 4 12 50.00%
Guard 3 3 14 47.50%
Guard 4 2 16 45.00%

All four of these guards are identical according to the Microlite20 system, but the results are slightly different under my system. Nothing is really dramatic in the results, even with very improbable NPCs (do you hire MIND 16 guards? Would a MIND 10 guard have a 5 subterfuge skill?)

For the sake of completeness, let's say that Aesir is opposing a lower skilled guard of average intelligence. Subterfuge skill rank of 2 and a MIND of 10. Under the standard Microlite20 system, Aesir has a 62.5% chance of success. Ties no longer go to the guard, but they don't go to Aesir either because there would be a re-roll. Under my system, Aesir has a 60% chance to succeed.

Why does it give a worse chance? The amount of change is less in my system. If you compare the original example, Microlite20 provided no advantage to Aesir. He and the guard were equal. In my system Aesir had a slight advantage, thus a higher chance for success as compared to M20.

Changing to scores provided Aesir a great advantage. Instead of being even with the Guard, he now enjoys a +3 advantage. That big of an advantage yields bigger results. In my system, Aesir already had an advantage over the first guard. Changing the skill and MIND score had less effect because the amount of advantage changed comparatively less.

Somehow I'm Awake, What Does All This Mean?

Advancement in Microlite20 provides for increasing Skill Ranks and Attributes. This makes the characters very high powered around 10th level. In my variation of M20, characters cannot change Attributes except by magic or optionally by age.

I hope this means that characters can be fun to play for more than 10 levels.

This also means that using Microlite20 as a platform to develop Andras helps me get the bones of the system working well. This will be easier to playtest, especially for newer GMs. This also allows me to playtest a solo version of M2010 (my system). Maybe I have been reading too much T&T lately, but having a solo version plus the Mythic GM appeals to me.

As always, more later.