On the Numbers — Advanced Old School Revival

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The target number in a roll is always meets or beats (for the person doing the rolling), whether that's a contested or uncontested check. In this section we'll discuss when high and low numbers matter to the fiction and how to assess difficulty when running the game.

Assessing Difficulty

The core rules describe what each TN means in the Target Number Difficulty table, but it's worth mentioning here that those descriptions assume a difficulty relative to the average adventurer, not relative to the character performing the roll.

That is, a "tricky" (TN 9) maneuver in scuba diving isn't "tricky" for a skilled hero with Domain Knowledge (Scuba Diving), it's tricky for an adventurer with an average 3 Mighty who has no skill in scuba diving. This means you will only very rarely need to call for rolling vs. an "easy" TN (5), because such rolls would be trivial (read: not meaningful) for most PCs.

Odds Behind the Scenes

Because dice explode on a d6 in OSR+, there's a ~16% chance on any given roll that a player will roll a critical success. This is contrasted with a critical failure, which actually has less than half a percent chance of happening on any given roll. Despite the vast disparity between these two percentages, playtesting reveals that players tend to believe that there is as much a chance of rolling a critical failure as there is rolling a critical success.

From a system POV, this is intentional. We want players to succeed, and we want them to succeed dramatically: this is built into the very math of the game. And when they do fail, we want them to fail dramatically, so that the very rare critical failure roll matters to the narrative.

Dramatic TNs & Success Checks

Every roll does not require simulating a narrative outcome that equals its rarity, however. When you call for an uncontested check vs a TN, there are no "degrees of success" and so the result is binary. In this case it doesn't matter if the player rolled a 7 on the dot or a 21; while you're welcome to narrate their success in a way that exemplifies how easily they beat the TN, there aren't any mechanical benefits for rolling so high on an uncontested check. This is also true of attacks in combat or defense rolls.

Which is Better, +2 or Advantage?

Very simply: conferring advantage on a roll is more or less the same as conferring a +1, as far as the numbers are concerned. So if you're weighing conferring a +2 vs. advantage, remember that the +2 is more beneficial than advantage.

Also remember that doubled advantage is a thing. If a PC has advantage on Deft from their origin but is also a Rogue who gets advantage on tinkering, they roll 3d6 instead of 2d6 when they tinker, because they have advantage from two different sources.

When in doubt, apply advantage and let the core rules handle the rest.

Assessing Attributes

Attributes quantify a combination of natural talent and learned experience, ranging from 0 to 11, with an average score being 3. This is because a PC starting with a 6 in an attribute can only ever gain a +5 to a single attribute through level advancement, assuming they slavishly dedicate every other perk through level 10 to that attribute. Realistically, however, most well-rounded heroes will cap out their favorite attribute at 8 or 9.

These upper bounds for attributes are true for both NPCs with stats and monsters; if you create NPCs with stats that exceed these numbers, most rolls involving the attribute will become trivial for them.

What the Numbers Mean

Remember that your average non-adventuring NPC doesn't have an attribute score (it's effectively 0, and they just roll a d6, exploding on a 6.) This means that adventurers are always exceptional people who are a cut above the average townsperson who's never left home. To get a handle on just how exceptional adventuring characters are, imagine each attribute point as representing a logarithmic scarcity in the population of people who have that score:

1: 1 in 10 people
2: 1 in 100 people
3: 1 in 1000 people
4: 1 in 10,000 people
5: 1 in 100,000 people
6: 1 in a million people
7: 1 in ten million people
8: 1 in a hundred million people
9: 1 in a billion people
10: 1 in 10 billion people
11: 1 in 100 billion people

At 10 in an attribute, we see the scarcity increases to (less than) a single person on the Earth with the score!

This also implies that each point in an attribute represents a tenfold increase in competence. Someone with a 5 in an attribute is fifty times more competent than someone with a 1.

Zero Doesn't Mean Incompetent

A common misconception with attribute scores is that a 0 means incompetence for a PC, when in fact it means lack of competence. These are two different things, because PCs are adventuring characters who are generally competent people all around.

When a character has a 0 Smart, for example, it doesn't mean they are a drooling idiot (although you could play them that way), it means they have no familiarity whatsoever with book learning (as it were) and lack any natural talent to excel in it: this puts them on par with the average townsperson we described above, who just rolls a d6.

Consider the below table for a less mathematical representation of attribute scores.

Example Table: Assessing Smart Scores

ATtribute	COmpetence	Example
0	Your average townsperson who is not literate and has received no formal education. Their learning comes from personal experience rather than study of any sort.	The stableboy's parents were neither rich nor educated, so all he knows are the horses and how to take care of them. His ambitions do not stretch beyond the town of his birth.
1	Such heroes have a vocation they learned by rote, likely as an apprentice or from a family member. They may not be literate and have no formal training, but they know this vocation well.	Barmaid Lala took over the inn after her mother passed and all she's ever known is how to run the business. The townsfolk love her because she's good at her job.
2	Such heroes have received the equivalent of high school instruction. They may be literate, but they are not knowledgeable outside their vocation and remain unfamiliar with academic subjects of any depth.	A squire who's completed his training is knowledgeable in chilvalry and the seven agilities, but the knighthood is all he cares to know.
3	Such heroes have received the equivalent of a college education. Their knowledge is well-rounded, but not specialized.	A wizard graduates from a magic school with good marks as a generalist, and is respected by his peers.
4	Such heroes have studied in a specialized field for many years beyond their formal education in order to contribute new research to it.	A promising detective who graduates top of class in spy school is recruited by the secret bureau to capitalize on her unique talents.
5	Such heroes are considered cream-of-the-crop minds who are destined to lead their peers in their field toward groundbreaking discoveries.	A irascible doctor who heads a prestigious academy, resented by his peers for his uncanny ability to save the day by knowing exactly when they get their diagnoses wrong.
6	Such heroes are considered geniuses in their field that will shape the way research is conducted in their generation.	The Einsteins of the world are one-in-a-million like this because they see the field itself in a new light, creating discoveries that change the world.
7	What's more genius than a genius? A polymath. Such heroes have mastered multiple domains of knowledge that would take more than one lifetime of study each!	Like his Renaissance Man- or Sherlock Holmes-analog, this multifaceted mind is born once across several generations, to solve problems that multiple seasoned minds wouldn't stand a chance to alone.
8	Such heroes are polymath visionaries who combine multiple fields to create entirely new fields of study that radically change the status quo. Cult followings often spring up around them in admiration or fear.	A seemingly messianic business mogul / mad scientist bridges the gap between profit and political power when his Clockwerk inventions end up forming the basis for an international monopoly.
9	The mind that's one-in-a-billion flips the old saying, "Jack of all trades, master of none" on its head: these heroes only have a handful of peers in the world, and there's only a handful of domains of knowledge they haven't mastered.	If the world is secretly ruled by a shadowy cabal, these heroes would have a seat at the table.
10	Literally the smartest person on the planet.	Ozymandias from Watchmen comes to mind: his intellect is borderline supernatural. He's a master of countless fields of knowledge and his ability to reason ahead and against all outcomes makes it seem as though he can predict the future.
11	A hero with this high a score possesses so vast an intellect that those who have spent their entire lifetimes studying the field consider the hero to be beyond the ken of their understanding. Such heroes are so unlikely, you may find a single among multiple worlds full of people.	To converse with such a legendary mind as this, travelers must search across multiple realms in the Astral Veil; the thoughts of such characters are a mystery to all but those on their level: numbered among the gods!

(These descriptions assume we're talking about a fantasy game in a medieval setting, as opposed to say a genre like scifi where the expectations for education would be vastly different.)

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