Percentage Based Skills - 2nd Look

About a month ago I presented a percentage-based skill system that converted all the x-in-6 chances from OD&D and what I used in their d12 conversion for Onn Core Rules. Having been playtested by a friend of mine, Tom, and his gaming group for the last month, here is the refined system:

• Characters begin play with a base score of 8 + the character's relevant ability score + any additional adjustments (such as racial adjustment) = the base % chance of success.

For example, Cedric the Elf Magic-user has an Intelligence score of 16. His chance to Detect Hidden (secret doors and the like) is 8 base + 16 Int = 24%. Because he is an elf he gains an additional +10% to this particular skill for a total of  24 + 10 = 34%.

• When a character advances each level beyond 1st level, he adds 3 + his Intelligence adjustment and multiplies the result by 5. This number is the amount of skill points he can distribute among his skills as he sees fit, so long as no skill recieves more than 10 points.

For example, Cedric reaches 2nd level as a Magic-user. He gains 3 + 1 (Int adj) = 4 x 5 = 20 points to distribute among his skills. He decides his Detect Hidden has been very useful and allocates 10 points to it, raising it up to a 44% and distributes the remaining 10 points into his other skills.

• [OPTIONAL] The Referee or player keeps track of how many times the characters use their skills successfully and relevantly for the game session. Once per session a player may declare he is trying to improve the skills a character has successfully used. For this roll, the player attempts to FAIL the skill check (rolling higher than their chance of success) and gains a +1 bonus to the roll for each tracked use of the skill being improved. If this reverse check is failed, the character gains a permanent +1% to their chance of success. Succeed or fail, the player wipes all tracked uses out and begins tracking anew.

Our elf Cedric's player decides to start tracking his character's skill uses with the Referee's approval. A couple hours into the session, the party hits a dead end and according to their mapper must be at the location of a secret door (based on what they found previously). Everyone in the party fails to find it. Cedric's player declares he is thinking back to all of the lessons his mentor taught him on how to stay safe and find very hidden things. The Referee tells Cedric's player he has 4 relevant skill checks for Detect Hidden so far and the player casts the dice against his 44%. He rolls a 41% and adds his +4 for his 4 relevant uses so far for a total of 45%. Failing the check, he gains a +1 to his chance of success in the future and is granted a reroll with his new score of 45%.

Typical use of this system is rolling equal to or under your chance of success (just like using Thief skills in older editions of the game). Onn doesnt have Thieves though, so this system also doubles for those players that likes those percentage dice.

 NO SKILL SYSTEM SHOULD EVER DICTATE THE FUN YOU ARE HAVING!!! IF A PLAYER GIVES YOU A THOUGHTFUL EXPLANATION OF SOMETHING COVERED BY SKILL USE AND YOU CAN'T SEE A REASONABLE EXPLANATION WHY HE SHOULD FAIL, THEN DON'T ROLL THE DICE! One trap is to over use the dice and make skill checks for everything under the sun. Some games run fine this way, but don't change your playstyle to accomodate a system...adjust the system for your playstyle.

Another view on Skills

Sometimes you can have too much time on your hands to think but never enough to do anything with it. I've been commuting 2 hours back and forth to work in Virginia the last 5 weeks and during that drive and sitting in traffic alot of great (in my mind) things have come out, but since I'm driving no real way to capture the details (something about the police around the Baltimore/DC frowns on out of state people doing things besides just driving, I dunno).

Anyways, everyone that knows me knows I have this love for the red-head stepchild d12. Using Onn's Ability Score adjustments of +/-2, you have more leeway for adjusting the results of a d12 then a d6 when making some kind of dungeoneering skill check. For those frowning now and about to think 'oldschool D&D' didn't have such things and this new school crap doesn't have a place in D&D or its clones, I'll simply say generally in the B/X and OD&D rules, most things had a flat 2-in-6 chance of success (with some Referees houseruling ability adjustments can affect this) and even Gary and Dave and other founding greats used ability checks and other systems to determine success of certain things considered 'skills'.

But enough of digression, if you're still reading you want me to get to the crunchy bits of the post. So I made Onn's 'Dungeoneering Skills' a d12 when I wrote the Core Rules. With the small modifiers ability scores have and the chances to do things (converted directly from the x-in-6 chance) it worked well as a flat system, but offers little room for growth for characters well-practiced (after levels and levels of doing them).

Early D&D and its clones and retro-games are all based around percentages, even if 'funky' dice are used. 2-in-6 = 33%, elves and their 4-in-6 chance to detect secret doors = 66%, heck even hobbits had a high percentage chance (depending on the version of the game, as high as 90%) to remain unseen outdoors. Since D&D-type games are class and level based, organic growth like a skills-based game dont work very well hand in hand normally. I've seen some houserules for combat and magic that severed the ties to class and level that looks very fun and dynamic.

One thing I thought up while I was driving back and forth was a percentage-based skills system. This is thoroughly untested (so far) but a short discussion with my home gaming group refined what was in my head to this:

1) Characters begin play with a base of 8% + the skill's relevant Ability Score.

Example: if a character has an Intelligence score of 13, his ability to Pick Locks would be 21% (8+13) at 1st level.

• Races and classes that have any bonuses to skills would multiply the bonus by 4 and add the result to their base chance of success.

2) During the course of a game session, the players keep track of successful relevant uses of their skills (dictated by the Referee). At the end of the session, the player rolls a check for each skill he used, adding +1% for each relevant use to his chance of success, but subtracting each level attained. If the check is a success, the player adds +1% to his chance of success.

Example: Our lock picking character has 6 successful attempts under his belt the Referee allowed him to record. At the end of the session, he rolls a Lock Picking check against a 27% chance of success (base 21+6). If successful, his base chance rises from 21% to 22%.

3) When a character attains levels beyond 1st level, he gains (3+Int adj) x 5 percentage points at each level. The points can be distributed as the player sees fit, but no more than 5% can be added to a skill at each level.

Example: Our character with the 13 Intelligence has a +1 adjustment. On attaining 2nd level, he gains 20 points ((3+1)x5) to distribute among his skills. He decides lock picking has been a useful skill so he allocates 5% to it, raising it up from a 22% to a 27%.

Using percentages allows the Referee more latitude in assessing bonuses and penalties and allows for some more organic growth without breaking the bank, so to speak.

Dungeoneering Skills for Onn

While some people decry using skills in D&D and D&D-clones as 'modernization', using ability checks and the x-in-d6 chance for things has existed since Original D&D first came out way back in the 70's. There were no Thieves in that very first game (they being added in Supplement I: Greyhawk) and all characters could perform 'dungeoneering skills' like sneaking and picking locks.

My first skill system for the World of Onn used a d12 with a 1-4 chance of success instead of a d6 with a 1-2 chance of success, because I like using modifiers for conditions, difficulty and ability scores (as a side note, this can make things as simple or as complicated as you let it be). Through the playtesting though, I found it easier to have a specific target number (much like the modern 'DC' D&D 3.x and 4 use). In addition, it just makes things easier to figure out on the fly when dealing with running a modern module and using Onn (or Swords & Wizardry).

I still use a Target12 system for my skills, finding a d6 too small to use with almost any modifiers, but a d20 way too huge and leading to skill bloat. Besides, the d12 is like a red-headed stepchild and needs some love (or maybe it's my odd liking of things...odd).

Dungeoneering Skills

Skill	Relevant Ability Score
Appraise Item	Intelligence
Climbing	Constitution
Decipher Writing	Intelligence
Detect Hidden	Wisdom
Disarm Trap	Intelligence
First Aid	Intelligence
Leap/Jump	Strength
Listening	Intelligence
Open Doors	Strength
Pick Locks	Dexterity
Sneaking	Dexterity
Swimming	Strength
Wilderness Lore	Intelligence

Of course, keeping Onn a retro-style game means the skill list should be small and these are the ones that have been the most relevant in both campaigns I've run. The skill challenge targets I codified in the following manner:

Dungeoneering Skill Targets

Difficulty	Target	3.x/4e DC	X-in-6
Very Easy*	6	5 or less	5
Easy	8	6-10	4
Average	10	11-15	3
Difficult	12	16-20	2
Very Difficult	14	21-25	1
Nearly Impossible	16	26+	1-in-d8

*Only roll if character is under duress or failure has major impact, otherwise use your judgement.

This was done for two reasons: 1) since all the new material is written for a skill system like 3.x/4e it's easier to have some form of conversion written down to keep things consistent; 2) Having a solid targtet number to work with keeps the game flowing smoother if you're using any skill system. The Target12 system still uses a d12 to roll the check and is basically the following formula:

d12 + any racial adjustment + relevant ability score adjustment + misc adjustments

If you equal or exceed the target number, you have a success. A natural 12 is also considered an automatic success and a natural 1 is an automatic failure. As noted many times though, the Referee should use his judgement where skills are concerned. If a character has set himself up to succeed by creating favorable conditions and/or is using the proper tools for the job (with a proper amount of stress-free time), then generally they should succeed at any difficulty of task eventually.

One may also notice that there are no social interaction skills. Charisma can be used to affect the reactions of NPCs and monsters and the degree of success (or failure), but a die roll should never be used to replace the social aspect of a ROLE-playing game, as discussed many times at length (such as the last post and across the OSR blogosphere).

I may use this expanded version of skill challenges in Onn's 2nd printing, but even though it works well for me I don't know if the feel is right for the retro-feel I want Onn to have.

Skill Challenges and When to Roll

Where D&D is concerned, some people consider it an 'evolution' of RPGs to have a 'singular' or 'unified' mechanic that everything can be formulized down into. The 3.5e and 4e games took this concept (which in truth has been around for a long time in other game systems) and ran like the wind with it. One of the side effects (or possibly the driving forces) behind this is the codification of skills in a class and level-based game system. Is there a reason why a character gets better at weapon smithing if he spends 3 months earning a few levels and is in a dungeon a majority of the time? How does he learn about smithing and practice it while he's down there? Other skills are more appropriate to everyday adventuring, like searching (and knowing where to search) and sneaking. Adventurers practice these skills every day of their lives.

The other side of the coin is when do you make a character roll a skill check and how often is it important? I embrace the randomness of the dice at every opportunity in my own games. But, that's where they become tools for creativity and not enslavers to the rules. Actual skill checks are made when I deem it important to know if a character can fail at such a task and if said task has reprecussions that could have a major effect in the game. Case in point: a 1st level Ranger I would have roll a skill check when encountering tracks to determine if he can tell the aproximate age, number of creatures and type of tracks. Does he know the difference between a giant and an ogre? The same Ranger at 9th level I would simply give the character the 'simple' information, but make a check for anything more exotic, such as if any appeared to be weighed down (with treasure or captives) or if any appear wounded or decrepit (by the way one particular set of tracks compared to others of the same type).

Player knowledge and actions play an important role at my table as well, which is why I frown on systems that use their unified mechanic where role-playing can be an important part of the game, such as when gathering information or dealing with an important NPC. Now, not every player has incredible social skills or the intimate knowledge of the campaign world's peoples, but if a player makes an honest attempt and uses whatever knowledge the party has gained through its adventuring then he should succeed. If a 'skill check' is needed for some reason for any type of PC to NPC interaction, the Referee should roll a check to the NPCs reactions and apply the speaking character's Charisma adjustment to the roll, along with a bonus of his choosing that reflects how much the player is using the knowledge the party has gained that might be relevant to the NPC. For this, I love players that take notes. Sometimes I give out alot of information. Usually most of it isn't relevant at the immediate moment, but down the road the tidbits become useful. When a player takes the time to commit the information to memory via notes and then uses them later in the campaign, I know they are enjoying the campaign because they are interested in what's going on (some people don't ever need to take notes and can quote something you said 6 months ago, these types of players are just as good since they are 'living notebooks'). In these cases, I treat all hostile results as indifference, unless the player is making some huge blunders when interacting with an NPC that simply cannot be overlooked (and this happens in real life as well on occasion, so you can use it to generate more adventure opportunities so the adventurers can 'save face' with the NPC group in question).

The players' knowledge should never be confused with their characters' knowledge, but they should be allowed to play the part of their characters when given the opportunity. Telling a player that he cannot do something because his 'skill level' isn't high enough flies in the face of the old school notion that characters can attempt do anything, even if they don't have a good chance for a favorable outcome.

Character Skills

One of the simplistic and fun parts of OD&D and the Swords & Wizardry retro-clone (pre-Black Blade Publishing's involvement*) is the exclusion of the Thief class. The early game assumed that all adventurers could do actions not defined by their class. The inclusion of the Thief later on slanted the game in perception if not mechanically that you need a Thief to do things that were the province of the common adventurer before.

The World of Onn is a Thief-free game that uses a simple skill system that builds from the early editions of OD&D and B/X D&D that uses the 33% (or 2-in-6) chance that a given action will succeed if a die roll is called for. The core mechanic for Onn's Skill System is the use of d12's for skill attempts that require a die roll. The base chance of success is a roll of 1-4 (the same 3% chance as 2-in-6), with the chance of success modified by the character's relevant ability score adjustment. So a character of 16 Dexterity (+1 adjustment) would have a chance of success of 1-5 on a d12 to pick a standard lock, while an 8 Strength character would have a 1-3 chance of success on a d12 to climb a wall.

Optional Skill Rules for Onn (and Swords & Wizardry)
No character is restricted from performing any activity. Each adventurer can try to sneak up on their enemies, pick the lock on a chest that hopefully contains treasure and magic, jump across a wide pit in their way and the like. As an optional set of rules additions, characters can acquire skills that increase their chance at performing various activities. While some characters will find some skills mesh well with their chosen class, no skill is barred from a character based on his class. Characters begin play with 4 Skill Slots. A character’s Intelligence adjustment also affects the starting number of Skill Slots, adjusting the total number from 2-6 (3-5 if using S&W's -/+1 limit for ability score adjustments). Characters gain a new Skill Slot at 4th level and every 4 levels beyond (8th, 12th, etc).

At 1st level, characters must use each slot for a different skill. After 1st level, when a character gains additional slots, he may use them as he sees fit. For example, if a character decides he wants to be better at sneaking he may dedicate 1 slot to the Sneaking skill at 1st level and then dedicate another slot at any level he gains a new slot after 1st level.

When required to make a skill check (if success is not guaranteed), the procedure is the same as using ‘Dungeoneering Skills’, 1-4 chance of success on a d12 modified by the relevant Ability Score adjustment, with the following modifier - for each slot dedicated to a skill the character’s chance of success increases by 1. For example, if a character with a 13 Dexterity (+1 adjustment) and 2 Skill Slots in Lockpicking (+2 bonus), would have a base chance of success of 1-7 on a d12 to pick standard locks. The Referee may assess a modifier to the chance of success based on the conditions the skill is being attempted in. The amount of time required to perform a skill must also be determined by the Referee - picking a lock could take 1 turn or less (or 1d10 rounds), but a Decipher Writing check to translate an ancient scroll could take an entire day.

You can help another character achieve success on some skill checks by making the check in a cooperative effort. In many cases, another character’s help won’t be beneficial, or only a limited number of characters can help at once. Generally the chance of success should gain a +1 bonus if the help of additional characters is relevant.

The list below is a sample list of skills. Referees are free to add or remove any skills they wish, and to define the skills how they are to be applied in their individual campaigns.

SKILL - RELEVANT ABILITY

Appraise Item Intelligence
Balance Dexterity
Climbing Strength
Concentration Constitution
Decipher Writing Intelligence
Disable Trap Intelligence
Disguise Charisma
Endurance Constitution
Escape Artist Dexterity
Forgery Intelligence
Gambling Wisdom
Healing (First Aid) Wisdom
Jumping Strength
Leadership Charisma
Listening Wisdom
Opening Locks Dexterity
Perform Charisma
Read/Write (language) Intelligence
Riding Dexterity
Ritual Casting Constitution
Searching Intelligence
Speak Language (language) Intelligence
Sneaking Dexterity
Swimming Strength
Tumbling Dexterity
Wilderness Survival Wisdom
Wrestling Strength/Dexterity

*I mention this because one of the conditions Black Blade made to produce the book for brick and mortal sales was to provide more 'meat' in the Swords & Wizardry Core Rules book. In order to do this, some optional classes were added, including Thieves, among other things. Even though I'm not personally an advocate of the Thief class, I don't disparage anyone else's game for including them. This isn't a negative thing in my mind, just a fact of record.