Drohem Posted October 3, 2015 Report Share Posted October 3, 2015 I need help from a math wizard to explain to my group the difference between how Skill Bonuses/Penalties are being applied by currently in our game play. Certain members of my group believe that there is no relative difference between applying a Skill Bonus/Penalty to the Skill Roll Needed or applying it to the actual Dice Roll. Let me explain with an example: Let's assume that my character has a normal Perception roll of 12- and he needs to make a roll with a -2 penalty. My group believes that making the Perception roll of 10- is mathematically equivalent as... Rolling 3d6+2 against a PER 12-. My gut tells me that they are not mathematically equivalent, but I don't know how to explain it properly. Or, I could be totally off base and they are mathematically equivalent, LOL! Either way, I would appreciate help from someone to parse it down for us math laymen. Quote Link to comment Share on other sites More sharing options...
Hyper-Man Posted October 3, 2015 Report Share Posted October 3, 2015 "3d6+2" seems like something that would only make sense in a Roll OVER system. Quote Link to comment Share on other sites More sharing options...
Lucius Posted October 3, 2015 Report Share Posted October 3, 2015 I need help from a math wizard to explain to my group the difference between how Skill Bonuses/Penalties are being applied by currently in our game play. Certain members of my group believe that there is no relative difference between applying a Skill Bonus/Penalty to the Skill Roll Needed or applying it to the actual Dice Roll. Let me explain with an example: Let's assume that my character has a normal Perception roll of 12- and he needs to make a roll with a -2 penalty. My group believes that making the Perception roll of 10- is mathematically equivalent as... Rolling 3d6+2 against a PER 12-. My gut tells me that they are not mathematically equivalent, but I don't know how to explain it properly. Or, I could be totally off base and they are mathematically equivalent, LOL! Either way, I would appreciate help from someone to parse it down for us math laymen. A roll of 3d6 has 16 possible results (some much more likely than others): 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 If we say that any roll of 10 or less is a success, and mark successful rolls as bold it looks like this: 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Simply counting them up means you have 8 results that succeed, and 8 that fail. If you want to add 2 to the roll, you get something like this: 3+2=5 4+2=6 5+2=7 6+2=8 7=2=9 8+2=10 9+2=11 10+2=12 11+2=13 12+2=14 13+2=15 14+2=16 15+2=17 16+2=18 17+2=19 18+2=20 If we count any result of 12 or less as success and mark success with bold we get this: 3+2=5 4+2=6 5+2=7 6+2=8 7=2=9 8+2=10 9+2=11 10+2=12 11+2=13 12+2=14 13+2=15 14+2=16 15+2=17 16+2=18 17+2=19 18+2=20 Again, we have 8 possible successful rolls and 8 possible failures. Where's Hugh Neilson when you need him? He's better at this stuff than I am. Lucius Alexander The palindromedary thinks I got the right answer but I'm not so sure. Quote Link to comment Share on other sites More sharing options...
Drohem Posted October 3, 2015 Author Report Share Posted October 3, 2015 LOL! Well, it's not the first time, nor will it be the last time, my gut has been wrong. However, does this account for degrees of success? I mean let's say in both examples that the raw dice roll is a 7. In the first example the degree of success would be 3, and in the second example the degree of success would only be 1. Quote Link to comment Share on other sites More sharing options...
Lucius Posted October 3, 2015 Report Share Posted October 3, 2015 LOL! Well, it's not the first time, nor will it be the last time, my gut has been wrong. However, does this account for degrees of success? I mean let's say in both examples that the raw dice roll is a 7. In the first example the degree of success would be 3, and in the second example the degree of success would only be 1. If by "degree of success" you mean "difference between actual roll and the highest possible successful roll" then the answer is 3 in both cases. If you mean something else, you will have to explain. Lucius Alexander The palindromedary says any degree from an accredited institution is a degree of success Quote Link to comment Share on other sites More sharing options...
Drohem Posted October 3, 2015 Author Report Share Posted October 3, 2015 Let me see if I can explain this in any meaningful way, LOL.... Example 1: Character has PER 12- Skill Penalty to roll is -2 Before dice are rolled, his roll for success is at 10- 3d6 are rolled and result is a 7 The degree of success is 3 Example 2: Character has PER 12- Skill Penalty to roll is -2, but it is applied to dice roll 3d6+2 are rolled, and the result is 9 [7 (raw dice roll) + 2 (penalty)] The degree of success 3 OK, you're right, it does seem that there is no mathematical difference between the two approaches. Thanks for the help! Quote Link to comment Share on other sites More sharing options...
Hugh Neilson Posted October 3, 2015 Report Share Posted October 3, 2015 Agreed - it does not matter. In either casem, rolling 10 or less on the dice succeeds, so the odds of success cannot have changed. Quote Link to comment Share on other sites More sharing options...
Lucius Posted October 3, 2015 Report Share Posted October 3, 2015 So it's just a question of which you find easiest to understand or explain. Lucius Alexander I find the palindromedary easy to understand but hard to explain Quote Link to comment Share on other sites More sharing options...
Manic Typist Posted October 4, 2015 Report Share Posted October 4, 2015 Well. It does matter somewhat. If you have 3 Penalty Skill levels to offset the use of a certain type of weapon... but the weapon your are wielding only imposes a penalty of -1.... then you only use 1 of your PSLs. So, to use their terms, they'd still add +2 to the roll. Or am I wrong about PSLs? The point I am trying to make is about the difference between PSLs and CSLs, or other Skill bonuses. Quote Link to comment Share on other sites More sharing options...
IndianaJoe3 Posted October 4, 2015 Report Share Posted October 4, 2015 If you have 3 Penalty Skill levels to offset the use of a certain type of weapon... but the weapon your are wielding only imposes a penalty of -1.... then you only use 1 of your PSLs. So, to use their terms, they'd still add +2 to the roll. Or am I wrong about PSLs? If I interpret you correctly, you are wrong. Penalty Skill Levels can only offset penalties, not give a character a bonus. To use your example, you could only use 1 PSL to neutralize the penalty the sword imposes. The other two would remain unused. Quote Link to comment Share on other sites More sharing options...
Manic Typist Posted October 4, 2015 Report Share Posted October 4, 2015 ...that's exactly what I'm saying. I then attempted to translate it into the preferred language of his players, who interpret penalties as adding to the 3d6 roll. So a -1 Penalty from a weapon would be 3d6+1 roll for success (assuming no other modifiers). If you had 3 PSLs, however, it would be 3d6+0, with the remaining 2 PSLs not being relevant. Where I was unclear was that I was still allowing for the OTHER negatives from the original example, that would NOT be covered by Penalty Skill levels. My bad. I meant to make it clear that the other 2 PSLs could not counteract some other kind of -2 modifier unless it was specifically relevant to what the PSLs had been purchased for. And that's why it could get a bit confusing if you turn all the negatives into pluses added to the roll, although it might just work better for that group. Quote Link to comment Share on other sites More sharing options...
Drohem Posted October 4, 2015 Author Report Share Posted October 4, 2015 Well, let me try to add some clarification to the situation. It's clear from the rules that skill bonuses/penalties are applied to the Skill Roll rather than the actual dice roll. My group plays online via Roll20 and the use of Macros. These macros are written and used when a roll is needed. The whole reason for this discussion because of the nature of online play and macros. Now, this isn't really an issue with combat rolls because of the formula for combat rolls and how modifiers can be applied in the macros. With combat macros, it's non-issue because the net modifier is applied to the base 11 and the actual 3d6 dice roll remains untouched. However, due to the nature of writing macros for Roll20 it is easier to apply the net modifier to the actual 3d6 dice roll rather then having to manually adjust the Skill Roll needed for every single attempted skill roll. I just had some doubts if there was a mathematical equivalency between applying the net modifier to the Skill Roll or applying the net modifier to the actual 3d6 dice roll. I suspected that the percentages of success or failure between the two approaches might be different and not match up. However, from Lucius' responses above it appears that there is a mathematical equivalency between the two approaches and I don't have to re-write the macros for our games. Quote Link to comment Share on other sites More sharing options...
zslane Posted October 5, 2015 Report Share Posted October 5, 2015 Skill Roll modifiers involve nothing more than addition/subtraction. Addition and subtraction are transitive. Therefore it does not matter which side of your equation the modifiers appear (as long as you get the sign right). Quote Link to comment Share on other sites More sharing options...
Greywind Posted October 5, 2015 Report Share Posted October 5, 2015 Quote Link to comment Share on other sites More sharing options...
Drohem Posted October 7, 2015 Author Report Share Posted October 7, 2015 Good song. I have no idea how it relates to the discussion though. Quote Link to comment Share on other sites More sharing options...
Greywind Posted October 7, 2015 Report Share Posted October 7, 2015 ...as long as you get the sign right... Quote Link to comment Share on other sites More sharing options...
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