skill rolls difficulty level in 7e

[mrjam]

Hello,

it is not clear to me the math about the skill rolls difficulty level in 7e.

Just as example, stealth vs spot hidden: it seems that the difference in success probability against an NPC with 49% spot hidden or an NPC with 50% spot hidden is pretty substantial (you use your full stealth skill against 49, just half against 50), while you have the same success probability against an NPC with 50% and an NPC with 89% spot hidden (half skill).

Have I misunderstood something?

Thanks

Edited July 8, 2019 by mrjam

[klecser]

Call of Cthulhu deliberately establishes skill breaks for expertise for certain skills. 50% is considered "Professional." By the time you have invested enough in a skill to have it at 50% or higher, you essentially are granted skill-specific "professional perks" with it. Once you hit 50 in Spot Hidden or Listen (two of the most critical skills in the game), it is just much, much harder for someone to sneak up on you. Another example would be the Other Language skill. Once you hit different milestones in numbers, you can execute certain communication abilities without making rolls. Example: At 30% you can conduct transactional business without the need for a roll. At 29? Nope. It is an incentive to use skills to proc improvement rolls.

A flavor consideration could be that it is harder for you to be BOTH well-hidden AND quiet than it is for you to just see or just hear something. So, the designers (I think) made the decision to make "hiding" more difficult than just hearing or just seeing. @Mike M or @Paul Fricker, am I understanding the design intent behind the "expertise break?"

Spot Hidden and Listen are critical investigative skills in the game and the pendulum swings both ways. If we reverse your example and have an Investigator with 50% spot hidden, it is setting a Hard difficulty level for opponents to sneak up on them. The Investigator is so good at Spot Hidden that they have gained a bonus "perk" for investing in the skill. So, it is important to keep in mind what the NPC skill value is for Keepers to be sure the challenge is where they want it to be for investigators.

1 hour ago, mrjam said:

while you have the same success probability against an NPC with 50% and an NPC with 89% spot hidden (half skill).

For this specific example I think it is worth noting that this game does not define Stealth/Spot Hidden or Stealth/Listen as opposed rolls. All the game establishes is that the skill level of your detection skill sets the difficulty for Stealth. So, yes, there is no numerical distinction for setting a difficulty level for Stealth if the detection skill is any number over 50. It is all the harder to sneak up on someone who is professionally trained to detect things. That means that is also generally harder to be sneaky in this game than to detect things. A rationale behind that is that it keeps the action and the narrative moving.

You have several options here: 

1) Option 1 is to play it as written. There is a deliberate numeric bias set up in the game that gives investing in detection skills a point-for-point advantage over investing in Stealth. Its an investigative game and skill points are limited. This gives the player more value in bringing Spot Hidden or Listen to 50. 

2) Option 2: House-rule it to what you want it to be. Maybe you want Stealth to be just as advantageous as Spot Hidden or Listen and you remove the "expertise break" of the two detection skills.

 

[mrjam]

3 hours ago, klecser said:

If we reverse your example and have an Investigator with 50% spot hidden, it is setting a Hard difficulty level for opponents to sneak up on them.

In this case the player should roll spot hidden against the stealth skill of the NPC, so going from 49 to 50 for the player gives just a +1%. My understanding is that the NPC skill set the difficulty level, not vice-versa.

Edited July 9, 2019 by mrjam

[klecser]

"Opposing skill/Difficulty level:
When attempting to hide, the opponent’s Spot Hidden
or Listen skill is used to set the difficulty level for the roll.
Situational modifiers may also apply (e.g. darkness or loud
noises)."

Page 77 Rulebook. The NPC is trying to hide. The "opponent" is the Investigator, who sets the difficulty level. An investigator with a detection skill of 50 sets it to Hard.

[mrjam]

3 hours ago, klecser said:

"Opposing skill/Difficulty level:
When attempting to hide, the opponent’s Spot Hidden
or Listen skill is used to set the difficulty level for the roll.
Situational modifiers may also apply (e.g. darkness or loud
noises)."

Page 77 Rulebook. The NPC is trying to hide. The "opponent" is the Investigator, who sets the difficulty level. An investigator with a detection skill of 50 sets it to Hard.

On page 83 of the rulebook it is indicated that it is the PC that roll a spot hidden skill roll using the NPC stealth skill to set the difficulty level:

"Wherever possible, the situation should be framed in such a way that the dice are being rolled by the player. [...] If the investigator is attempting to use their Stealth skill to furtively follow a non-player character, the player would roll the dice and the Keeper would use the non-player character’s Spot Hidden skill to set the difficulty level. If the situation were reversed and the non-player character were following the investigator, the player would roll the dice against their Spot Hidden skill to see if the tail is spotted, but this time Keeper would use the non-player character’s Stealth skill to set the difficulty level."

 

[klecser]

I read that more as an example of Keeper adaptation to a particular situation and preserving the spirit of "player acts" over "NPC acts."  I'd encourage you to play it in whatever way makes sense in the moment. 

I think you may be seeking objectivity in a game that is intended to be deliberately more squishy. Call of Cthulhu is first and foremost about role-playing. 

Edited July 9, 2019 by klecser