Applying Modifiers

[M. J. Young]

As often happens to me, this thread has appeared and exploded during the day, and I'm thinking I should add to it but am having trouble sorting out my input.

The original question concerned whether to add a bonus to the chance of success or subtract a bonus from a die roll; yes, people would prefer to add than to subtract; I'm not convinced it's that big a deal. Yes, addition feels more like a bonus, but it can work the other way around (particularly if you invert the system, such that high rolls succeed and low rolls fail).

We use percentiles with many different kinds of modifiers in Multiverser; sometimes you subtract from your die roll, and sometimes you add to your chance of success. But because of the fact that the die roll means more than pass/fail, these have different outcomes. If that's not relevant in your case, that wouldn't matter.

Of greater concern, you might consider whether normal play is going to place targets closer to the top or the bottom of the scale. If play is going to involve a lot of probabilities of success that are close to 100%, increasing the probability of success to greater than 100% (theoretically, as a target number) means that the player will feel he has lost the benefit of his advantages, because he can't roll that high; reducing his roll will work better in that regard. At the other extreme, if very low probabilities are the norm, increasing his chance of success will "feel" like it's upped his odds more than decreasing his roll. It's a psychological thing, but very much part of player reactions.

On your damage multipliers, I'm not sure I'm getting it; however, I think the formula works out (allowing for the imperfections of odd outcomes in division) such that all the variance between skilled and unskilled characters is in whether or not they hit at all; damage multipliers are based entirely on their chance of success, and thus scale with that chance of success. That is, ten percent of all hits will do triple damage, regardless of whether they are dealt by experts or novices. The expert does triple damage more often only because he hits more often; the ratio of hits which do this extra damage against those which do normal damage is the same as the novice--always one out of ten hits.

This would seem to go against

So a highly skilled swordsman is more likely to hit where it hurts....

He is more likely to hit more often, but any given hit has the same average damage characteristics as the completely unskilled character.

Unless I misunderstood?

Also, if, as it seems, you're using the die roll to determine this aspect of damage, whether or not relative to the target number, negatively bonusing the die roll will impact this outcome (since it appears in your analysis the low roll is best, it will increase average damage by favoring multiple damage results). If you increase the target number but don't adjust the scale (that is, the probability of a multiple damage result is based on the unbonused chance of success) you do funny things to the outcome--you will increase the total number of hits, but decrease the proportion which receive bonused damage.

Multiverser ties damage to the roll directly; it also ties it to the character's skill independent of the roll. The latter aspect is that a character with skill of a professional level automatically doubles damage (actually gets a damage category bonus, which varies in value depending on the base damage category, but is close to doubling in most instances). The former aspect uses the attack roll to determine damage. Because greater chance to hit means you can roll higher and still hit, the character with the greater chance of success not only hits more but averages more damage on a hit.

You could achieve a similar effect with thresholds. For example, set your thresholds at 50 and 80 (Multiverser uses these as thresholds for certain kinds of skills that are not damage-related). If the character rolls a successful roll greater than 50, double his damage; if he rolls a successful roll greater than 80, triple his damage. In this way, the character with the better chance of success also has the greater chance to gain the bonus damage. It avoids the UA problem you cite (in which average damage per hit actually decreases with increased chance to hit due to the proliferation of straight damage success values), and the similar problem with your own system (in which average damage per hit never alters). When due to opponent skill or defenses the character has lower than a 50% chance to hit, he cannot score double damage--but this would reflect the idea that his skill is not sufficient to adequately penetrate the defenses. The greater the character's chance to hit, the more likely it is that he will get the double and eventually the triple damage.

In this case, it would make a significant difference whether you raised the success ceiling or lowered the die roll, as it would also impact the chance of getting that bonus damage. That is, if the chance of success is raised from 45 to 55, this gives the player a 5% chance that his roll will both hit and score double damage; if instead the die roll is reduced by 10 and the chance is 45, the character will still hit on a roll of 55, but will not score the bonus.

I hope this helps.

--M. J. Young

[Mike Holmes]

And you know, I haven't heard many things about it here, but GURPS combat always at least made sense to me, unlike the combat in many other games (Storyteller, Shadowrun, D&D, etcetera, etcetera, etcetera).

GURPS combat isn't terrible, but it's missing a critical element that RC is looking for. He wants damage to be influenced by skill. This is something that a lot of people fault GURPS for, though YMMV.

But there are a great number of games that do this well, TROS being the obvious example that we all agree on.

Mike

[redcrow]

First, let me say thanx to everyone for your input, ideas, and suggestions.  

This would seem to go against

So a highly skilled swordsman is more likely to hit where it hurts....

He is more likely to hit more often, but any given hit has the same average damage characteristics as the completely unskilled character.

Unless I misunderstood?

Sorry, my poorly worded example at fault.  Let me try again...  

A highly skilled swordsman knows where to strike to do the most damage and is likely to hit in those places more often.  A less skilled swordsman also knows where to hit to do the most damage, but is likely to hit in those places less often.

Multiverser ties damage to the roll directly; it also ties it to the character's skill independent of the roll. The latter aspect is that a character with skill of a professional level automatically doubles damage (actually gets a damage category bonus, which varies in value depending on the base damage category, but is close to doubling in most instances). The former aspect uses the attack roll to determine damage. Because greater chance to hit means you can roll higher and still hit, the character with the greater chance of success not only hits more but averages more damage on a hit.

I'm not familiar with Multiverse, so I'll have to check into it.  This may be an option for me to consider, though it sounds less dynamic than what I was trying to accomplish.  It may be a viable solution, though.

You could achieve a similar effect with thresholds. For example, set your thresholds at 50 and 80 (Multiverser uses these as thresholds for certain kinds of skills that are not damage-related). If the character rolls a successful roll greater than 50, double his damage; if he rolls a successful roll greater than 80, triple his damage.

I've seen systems that did something similar to this before, but I don't particularly like this method.  I like the idea that even a very low skilled person could get in a lucky shot and score incredible damage occasionally.  This method would make that impossible.