Follow up: Passive Perception and Insight in AD&D #ADnD #DnD #RPG 

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Yesterday, I published a post on how the wonderful 4th Edition D&D (“4e”) innovations, passive insight and passive perception, have 1st Edition AD&D (“1e”) to thank for their existence to some extent. They were so good that 5th Edition D&D (“5e”) kept them despite owing its quick existence to 4e hatred. PI & PP represent pulling back from the active checks of 3rd Edition D&D (“3e”). Some brief but extremely useful conversations took place on Facebook, so I hastily put together this post to take it a little further. I apologize for any typos or incomplete sentences. I’ll clean it up later tonight.

Note: The extent of my experience with other games is relatively limited.

All of this got me thinking. The problem with 3e skill rolls is metagaming. If the characters enter a room, and the DM tells the players to make Spot or Listen checks, and the players all roll 10s or less, they’re not going to believe the DM’s words, “You see nothing here.” Telling the players to roll those checks is basically giving away the secret, so I never saw a rogue try to pick a lock under analogous circumstances. That solution doesn’t work for me. Instead, I’m considering something I haven’t seen in D&D nor in any other role-playing game (see note above). My solution lies somewhere between 1e and 4e’s PI and PP. 1e has the monster’s stat block determine whether the PCs succeed or fail, which means that the DM rolls unannounced checks, and players aren’t aware that anything is up (i.e., reduces metagaming). That’s great, but it removes player agency over their own characters’ attributes and abilities. 4e PI and PP instead have the players’ character sheets factor in. The monster stat block sets the difficulty, but the PCs’ attributes and abilities modify their rolls appropriately (i.e., increases PC agency). At first, it seems like PI and PP are the best solution.

The Problem with Passives

But if they were, this post wouldn’t exist. When a game uses passives, the game designers build challenges around what the characters expected passives are going to be. In a situation where the game (or adventure) designer doesn’t want the characters to pierce an illusion or locate a trap, they can always set the difficulty (let’s call it a “TN” for “target number”) unreasonably high, but in most cases, you want the TN to be something nontrivial but obtainable, give or take based on whether it’s easy, moderate, or hard.

But the passive is a static number. There’s no wiggle room, so if, for example, a moderate challenge is desired, the designer picks a number that represents the average TN for the average character. However, every party is going to have at least one character that’s above average in the relevant check. And therein lies the rub. The above-average character’s passive score will always succeed against that average TN. Always. The nature of game design makes passives lean far too heavily towards successes even in a moderate or hard campaign. In hindsight, this is consistent with my experience throughout 4e and 5e.

Thus, while passives remain, in my humble opinion, an innovation, I’m now of the opinion that there’s something better we can use.

My Solution

As with virtually every issue I’ve raised in these posts, I’m probably not the first person to think of them. Screw it. I’m an asshole, so I’m still calling it “my” solution.

I prefer to keep the rolls behind the DM screen. Let the DM roll to determine success, which means there will always be at least some chance of a total failure and some chance of a total success. The high Wisdom character may still fail to hit an obtainable TN, but low Wisdom character may hit it instead. Everyone’s rolls matter, so everyone has their fun, but usually only the high Wisdom character’s roll will succeed, which means that character’s value will always be appreciated by the group. That character will get a chance to shine in the way in which the character was built to succeed. But that’s game balance, and that depends on the system’s math. I want a little more here because my primary concern is psychological.

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Disclaimer: Not a shrink.

So, use the 1e system generally, but allow bonuses and penalties based in part on the character sheet. That is, have the DM roll the dice, but modify the roll based in part on each character’s relevant attributes or abilities, which the DM can keep handy behind the screen. This avoids both the problem with static numbers and the problem of metagaming (in this narrow regard), and the players retain their agency. While you’re at it, you can add bonuses if the characters have encountered a (very) similar challenge in the past.

The problem now is how to handle that math for existing systems. I really like the 1e mechanic of rolling 3d6, and if the roll is at or below a relevant attribute score, then the character succeeds. That won’t always work, though. With the gas spore, it’s a percentile roll. A +1 bonus on a d100 is completely different than a +1 bonus on a roll against an attribute score or a regular d20 save. You’ll need a reasonable formular for each, accounting for both the range of possible values and the bonus or penalty given to the relevant attribute score. You may even want/need to account for class and race abilities.


But with the DM rolling, won’t characters know something’s up? Probably not. Once per round or once per encounter, the DM is expected to roll a surprise die, an initiative die, and a distance die in 1e, and occasionally will be expected to add in some extra dice rolls for equally mundane reasons. There are plenty of reasons to roll in most game systems, but if not, the DM can just make phantom rolls from time to time to throw them off the path. We always expect DM bullshit; it’s a problem only when we’re directed towards specific bullshit. In the end, no one should be the wiser.

Except for gas spores. Anyone who’s read my posts will probably be suspicious of any beholder I throw at them.


There’s one other thing to consider, though. What I’m describing is a small thing, but small things add up. Sure, this is an easy mechanic to grasp conceptually and implement practically, but it’s adding to the pile of other mechanics. PI and PP don’t add as much to the workload as what I’m suggesting, and every bit of complexity you can avoid makes for a faster game. Whether you’re considering what I’m proposing for your own game system or just to add to your existing RPG, keep that in mind.

If you’re modifying an existing system, good luck on the math.

Follow me on Twitter @gsllc

Dungeons & Dragons is a trademark of Wizards of the Coast, LLC, who neither contributed to nor endorsed the contents of this post. (Okay, jackasses?)


2 thoughts on “Follow up: Passive Perception and Insight in AD&D #ADnD #DnD #RPG 

  1. I prefer to roll play most skill checks, and I think that applies to passive perception as well. The trick is to get the players to announce their alertness level.

    While I haven’t systematized it, as a DM I keep track of how much attention the PCs are paying to their surroundings. Levels would be something like:

    Oblivious: When characters are in combat, memorizing spells, working to disarm a trap–totally focused on something. They won’t notice anything outside of what they are focused on unless it is a huge explosion or something of that magnitude.

    Complacent: Not being alert to what is going on around them. In town or other familiar area, I assume the PCs have let their guard down unless they specifically say otherwise. They will only notice something that calls attention to itself like a scream or a flash of lightning. (I also assume this level if the PCs are discussing what to do next for any length of time even if in a dungeon.)

    Alert: The default setting for delving or exploring a potentially hostile wilderness area. They will notice movement or landscape features that are out of place automatically. They will get a save to avoid a trap’s effects, but not see it in advance unless it is blatant.

    On Guard: When the players say they are checking for traps, probing the ground with a staff, examining doors before they open them, stopping to listen at intersections. I wouldn’t tell them they found a trap, instead say something like, “This stretch of floor here is a different color stone and is slightly raised.” and then let them experiment to find the trap.

    Close Search: Probing everything, checking for trip wires, hidden passages, looking at the undersides of tables and down drains. I’ll tell them where traps and secret doors are, but they still have to figure out how they work.

    I put the responsibility for discovering and avoiding hazards on the players. Tell me what you looking at and listening for, and I’ll tell you what you notice.


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