[Icar] Should I go from Percentiles to D10?

[brainwipe]

Something that's been bugging me for some time is the skill percentile system in Icar. Generally, it's not very easy to use. For the uninitiated, every skill has a percentage and to pass it, you have to roll 2 D10 under it. Now, I've always argued that it's quite easy to roll under something because you don't need to do any sums, you just compare. Is 22 (on the dice) less than 67% (on the skill)? Yes! Quite quick and simple.

The problem comes with modifiers and difficulties. I find myself having to ask how far under the skill the roll was more often than not. It's no longer simple comparison but brain-aching set of 2-figure subtractions and additions.

I'll give an example:
You have Heavy Firing skill of 67%. You're shooting someone at short range with a weapon that has a modifier of 20%. Therefore, your target number is 87%. That should be written on the weapon sheet you're using, so it should be simple to check so so far. But then you're trying to do something complicated, so you get a 55% modifier. Now you have to take away that from 87%. Bit of a pain, isn't it.

The Proposal
Some of you can see what's coming, no doubt. Divide the percentiles by 10. This would make the skill ranges 1-10, rather than 1 to 90%. Here's how the rules would be set up:

• Every skill is from 1-10.
  
• You have to roll under the skill value to pass.
  
• 10s are automatic fails (same as for Stat checks at the moment)
  
• 1s are automatic passes (same as for Stat checks at the moment)
  
• Difficulty levels will be reduced like they are for Stats at the moment
  
• 3 Roleplaying Points (read XP) needed to raise a skill, but only if ticked.
  
• (Under playtest) 4 Roleplaying Points and a good explanation needed to tenuously raise a skill if not ticked.
  
• The starting values for First Epoch skills will be based on a single Statistics. You get 1 if you stat is between 1-5 and 2 if your stat is 6 or more.
  
• Second epoch skills (one step up the skill tree) start at the previous epoch -3.
  

The Pros are that the maths becomes much easier. Our example above, (with adjustment) becomes a skill of 8, a modifier of 2, makes 10 and then you get a -6 modifier to that. Making 4. That's what you have to roll under on a D10. Much easier mathematics.

Furthermore, vehicle combat becomes much easier as there will be no need to divide by 10. The manouvre roll becomes Skill + D10 + Manouevre of Vehicle + Manouvre you're doing.

The Cons are that this is a lot of work. All the rules will need to change and all the equipment sheets will need updating (and rebalancing in some places).

Before I plum for this, I really do need some feedback and thoughts. I don't think it as a major change of feel, just a simplifying step but that's only because I've been listening to roleplaying podcasts and got my head full of newfangled ideas. Please let me know your frank opinions!

[Temple]

Have you considered converting to using a d20 instead of a d%? So every skill increases in incrementsof 5%? It becomes less granular than the 10%increase per step in a 1-10 version, and the math is still dead easy.

[brainwipe]

Skjalg, that's a very good point. I do like the additional granularity that a D20 provides and the maths is still easy. My gut reaction is that there is a lots of the rules that will need to change if I did that but there is a lot to readress anyway.

I shall certainly give that a good think and keep it in mind. Many thanks!

[Chris Crouch]

My 2c worth:

There are a couple of main advantages of D100 over d10/d20:
1) Finer granularity of advancement
2) Finer gradations of very low or very high skill levels

If your game doesn't need these things, then you probably should changed to a 10 or d20.

If you do want to stay with percentile, you can reduce you maths:
1) For difficulty modifiers that make things harder, you can make it so that you have to roll _over_ the difficulty modifer and _under_ your skill. This is mathematically equivalent, but no addition required. (eg: skill 67%, but -25% difficulty modifer due to say long range: you need to roll >25 and <=67 to succeed, which gives you the same 42% chance of success)
2) For easier tasks it's more complicated: you need to subtract them from 100, then any roll <skill or >ease is a success (in your example, 20% bonus for close range becomes ease 100-20=80, so a roll of <=67 or >80 becomes a success). Probably not worth it because it doesn't save much effort at all.

Chris

[Eldrad]

Keep your modifers on 10% increments.

ANything else is complicated and slows down play.

If there are too many modifiers then simplify and get rid of modifiers.

Simple and quick is better.

If the modifers slow down your game play get rid of them!

[sid.raphael]

Hi brainwipe.

When I deal with "skills vs difficulties" issues, i use this idea:
the number rolled to have a success must be greater(or equal) than the difficulty but lesser(or equal) than the target number.

Your example:

You have Heavy Firing skill of 67%.
You're shooting someone at short range with a weapon that has a modifier of 20%.
Therefore, your target number is 87%.
That should be written on the weapon sheet you're using, so it should be simple to check so so far.
But then you're trying to do something complicated, so you get a 55% modifier.

My hack;
Your target number now ranges from 55 to 87.

(so, 55 or 87 are successes, while 31 or 95 are failures)

Sid

[Callan S.]

The player writes down his percentage: Say it's 65%. That's classed as a D result.

He then writes down increments, in A, B, C levels of skill, in advance of play (next to each skill). Well use increments of 10% here

C is 55%
B is 45%
A is 35%

It's still easy for the player to see what he got. He then calls it out "I pass with a a B!"
The GM just has to think "He needs a B" rather than think of whether he beat it by 10% - if he gets it, he's passed. I don't think its hard for the GM to be thinking "He needs a B" and compute that when the player calls an A result, he's passed as well. It's pretty organic.

[Sydney Freedberg]

It's just a whole lot harder to add and subtract double-digit numbers than it is to add and subtract single-digit numbers. I'd say d10s are by far the easiest, d20s are nearly as easy, and d100 is a pain in the brain.

If you want granularity in character advancement, as Chris Crouch mentioned, I'd suggest requiring 10 XP to gain a +1 to your d10 roll; that's far easier to keep track off than each XP adding +1 to a d100 roll.

[Eldrad]

Callan has the best idea! Heck I might even use that!