Barding Success Chance - The real math

Calculating your barding success chance seems to be one big mystery here.

I've dug into the RunUO script files related in the calculation of the barding success chance and want to share my understanding of the barding success chance.

Every Mob has it's own barding difficulty - it's calculated from stats, skills and some bonuses for poison, firebreath and magery levels.
Let's not go too deep into how this is calculated - you can just determine it by using Animal Lore on the mob.

Now a mobs barding difficulty will soon be compared with your skill level and virtually range from 0.0 to unlimited.
It's NOT a success chance or any other percentage value ...

EXAMPLE NUTHATCH BARDING BASE DIFFICULTY : 100.0​

Now let's continue with this barding BASE difficulty. The first thing that is applied to this value is the bonus for exceptional or slayer instruments:

Code:

double val = GetBaseDifficulty( targ );

if ( m_Quality == InstrumentQuality.Exceptional )
    val -= 5.0; // 10%

if ( m_Slayer != SlayerName.None )
{
    SlayerEntry entry = SlayerGroup.GetEntryByName( m_Slayer );

    if ( entry != null )
    {
        if ( entry.Slays( targ ) )
            val -= 10.0; // 20%
        else if ( entry.Group.OppositionSuperSlays( targ ) )
            val += 10.0; // -20%
    }
}

This means that the barding BASE difficulty is reduced by 5.0 for exceptional instruments and 10.0 for matching slayer instruments.

Let's say we're fighting the example nuthatch with a simple exceptional/GM instrument:

EXAMPLE NUTHATCH BARDING INSTRUMENT DIFFICULTY : 95.0​

Now let's continue with the two simple barding skills Peacemaking and Discordance. They only affect a single mob so it's easier to calculate.

Both of those skills have another 10.0 barding difficulty reduction:

Code:

double diff = m_Instrument.GetDifficultyFor( targ ) - 10.0;

EXAMPLE NUTHATCH BARDING SKILL DIFFICULTY : 85.0​

This value is the basis for the success chance calculation. Simply said, this is the barding skill at which you have 50% success chance.

But there's more than that. Your success chance is calculated in a range +/- 25.0 around the barding skill difficulty.
So the example nuthatch requires a minimum peace/disco skill of 60.0 (85.0 - 25.0) for a barding attempt - with VERY little success chance.

EXAMPLE NUTHATCH MINIMUM BARDING SKILL : 60.0​

Now since +/- 25.0 is a range of 50.0 skill points and we're going from 0% success chance at -25.0 up to 100% success chance at +25.0, every 1.0 skill above the minimum barding difficulty gives you an additional 2% success chance.

So with 61.0 skill your success chance is 2% for the example nuthatch. A skill of 75 will give you a 30% success chance. It's 15.0 skill points above the minimum barding skill which can be converted to a success chance of 30% (15.0 x 2)

If you attempt to peace this nuthatch with GM peace, your success chance is 80% (your skill - minimum skill) x 2 = success chance %

It's just a LITTLE more complicated with provocation. The INSTRUMENT DIFFICULTY of both mobs is added, then divided by 2. Let's just call it the AVERAGE BARDING DIFFICULTY.
We want to provoke the nuthatch onto a Lich Lord with 109 BARDING BASE DIFFICULTY (104 BARDING INSTRUMENT DIFFICULTY for exceptional instruments)

EXAMPLE NUTHATCH VS LICHLORD AVERAGE BARDING DIFFICULTY : (95.0 + 104.0) / 2 = 99.5​

This average barding difficulty from both mobs is then reduced by 5.0:

Code:

double diff = ((m_Instrument.GetDifficultyFor( m_Creature ) + m_Instrument.GetDifficultyFor( creature )) * 0.5) - 5.0;

EXAMPLE NUTHATCH VS LICHLORD PROVO BARDING DIFFICULTY : 94.5​

Then we apply the +/- 25.0 math again. Minimum barding diff this time is 69.5 and the success chance at GM provo level calculates like this:

(100 - 69.5) x 2 = 61%

So you've got a 61% chance to make this nuthatch destroy the lich lord. Chances are you're next ...

Some simple things to keep in mind. I'll just assume you're barding skill is at GM level.
That means you have a 100% success to peace/discord mobs with 90.0 BARDING BASE DIFFICULTY
And you have a 100% success chance to provoke two 85.0 BARDING BASE DIFFICULTY mobs.

Another example calculation is provoking two Lich Lords with a silver instrument.

Both have a BASE DIFFICULTY of 109, minus 10.0 for the right slayer instrument results in 99.0 INSTRUMENT DIFFICULTY.

The average of two times 99.0 is still 99.0 which is reduced by 5.0 provo factor again to 94.0

If you subtract 25.0, you get the MINIMUM DIFFICULTY of 69.0 - a GM provo is 31.0 better than that and thus has a 62% success chance.

I have created a barding success chance calculator in excel

https://www.dropbox.com/s/wnjtv0eidxg8m8d/Barding_Calculator.xlsx

Looking for feedback !

Good work!
But how accurate is your calcul?

101% german precision.

Does this factor in the GM Disco bonus to Provo?

There is no general GM Disco bonus to Provocation.

Only when it comes to the calculation of the guaranteed success chance, GM Discord will give you 10% instead of 5% guaranteed success chance for very high level mobs.

Correct my if I'm wrong Telamon ... but that's what it sounds like to me.

Gotcha, so if the calculation comes out under 10%, it is 10%

Exactly, and if you don't have GM Discord, it's only 5% for the other two barding skills.

Is this still up to date?

That is one useful post if I ever saw one (+1)

I doubt it. UOR has slightly customized codes/values. Sadly, these seem to be confidential. You could start test series, e.g provo two lich lords on each other.

I tested Wodan's spreadsheet it with pirates, and it seemed pretty close. In any case, I think it is good that some game mechanics are confidential.

I totally agree, makes it more challenging!