|Can we discuss this like civilized people?|
Some of this confusion results from the misunderstanding of skill checks in general, but much of it is related to how powerful Persuasion can be when used. To clarify, let's start with skill checks in general. A skill check is just a special kind of ability check that allows the PC to add their proficiency bonus if they are proficient in that skill. Here are the Rules as Written in regards to ability checks.
To make an ability check, roll a d20 and add the relevant ability modifier. As with other d20 rolls, apply bonuses and penalties, and compare the total to the DC. If the total equals or exceeds the DC, the ability check is a success--the creature overcomes the challenge at hand. Otherwise, it's a failure, which means the character or monster makes no progress toward the objective or makes progress combined with a setback determined by the DM.
It is important to note what it does not say in the rules about ability checks. Unlike attack rolls, a roll of 1 is not an automatic failure, and a 20 is not an automatic success. Success or failure is only determined by the total (roll + bonus/penalties) matching or exceeding the DC of the skill check. This is a critical point. If the DC is 10 and the PC has a +9 as proficiency in a given skill (as is often the case with Rogues), that PC will always succeed on a DC 10 or lower check, even when rolling a 1. Similarly, if the DC is 30 for some impossibly difficult task, that same PC with a +9 proficiency will always fail even if the player rolls a 20 (short of some other circumstance adding to the roll).
Now let's look specifically at the Persuasion rules.
When you attempt to influence someone or a group of people with tact, social graces, or good nature, the DM might ask you to make a Charisma (Persuasion) check. Typically, you use persuasion when acting in good faith, to foster friendships, make cordial requests, or exhibit proper etiquette. Examples of persuading others include convincing a chamberlain to let your party see the king, negotiating peace between warring tribes, or inspiring a crowd of townsfolk.
Note that the rules mention "acting in good faith". This is to separate the circumstances between using Persuasion versus using Deception. There is a gray area between these two skills, but in general, if the PC is trying to lie or bluff their way through a situation, use Deception. If they are trying to influence an NPC (but without specifically lying), use Persuasion. It's a bit of a judgement call in some cases. For reference, here are the rules for Deception.
Your Charisma (Deception) check determines whether you can convincingly hide the truth, either verbally or through your actions. This deception can encompass everything from misleading others through ambiguity to telling outright lies. Typical situations include trying to fast-talk a guard, con a merchant, earn money through gambling, pass yourself off in a disguise, dull someone's suspicions with false assurances, or maintain a straight face while telling a blatant lie.
As you can see, the examples in the rules attempt to clarify the lines between Persuasion and Deception. Attempting to get an audience with the King is Persuasion. Deception is attempting to fast-talk a guard when you've been caught inside the Queen's chambers.
Persuasion is not mind control.
Based on my reading on social media, one thing that appears to trip new DM's up is what players can get away with using Persuasion. Persuasion is not the Charm Person spell. Persuasion is not the Suggestion spell. Just because a player rolls high does not mean they can ask for anything and the NPC will grant that request. As a DM, you are free to set the difficulty as high as you think it should be... even impossibly high if the situation warrants it.
If a stranger on the street came up to you and asked, "Hey can I take a look at your credit card for just a moment," would you give it to him? Look at the Persuasion actions of the PCs through that lens. Put yourself into the shoes of that NPC. Would you do what the PCs are asking?
Some things to consider:
- Does the NPC know the PCs?
- Does the NPC already implicitly trust the PCs?
- How much personal trust is required for the NPC to do what the PCs ask
- Or how secret is the information they seek?
- How much personal accountability or danger does the NPC take on by doing what the PCs ask?
Basically, how big is "The Ask"? No matter how urbane or charming a stranger on the street may be, I'm not about to hand over my credit card. DC 35, at very least.
Now, if your best friend came up to you and said, "Hey, I forgot my wallet and I want to buy that Funko Pop Drizzt. It's the last one, and I swear I'll pay you back!" Would you then give him the credit card (or loan the money)?
As the DM, you need to set the difficulty appropriately... and a 20 does not guarantee a success.
|Perhaps we should take an alternate approach?|
This is assuming the PCs actually are acting in good faith. But if the PCs are attempting to deceive, or perhaps their Persuasion doesn't give the NPC any direct benefit, a successful Insight might make the NPC hesitant, which leads me to...
Bribery is always a bit of a challenge to adjudicate. How much is enough? How little would be considered insulting? There are no good mechanics for considering bribery, except perhaps considering a) How much personal risk does the NPC take accepting the bribe? and b) How much value does the bribe hold for the receiver?
Offering a noble money is not likely to work. They risk their reputation, and they already have money to spare, so they would require a favor or object of great value. On the other hand, if you are just asking a guard or bartender discreetly for information, the risk is likely low, and a few gold is more than a week's pay, so that may go a long way toward loosening of lips.
Although Dungeons & Dragons does not have mechanics for honor or reputation, other tabletop RPGs often do (some of which can be easily adapted to D&D). Even if you do not use this kind of mechanic in your game, you can think back across the course of your campaign and consider what kind of reputation the PCs have built for themselves.
- Are they heroes?
- Have they acted honorably and charitably?
- Do they have the trust of leaders and kings?
- Or have they left villages in ruin?
- Do they have an innocent bystander body count?
- Have they betrayed and murdered their way across the countryside?
- Are they famous or infamous?
Even in a pre-telecommunications society, these events and stories will get around and the party's reputation will suffer. In a world where magical communication or bardic stories are spread far and wide, the PCs may find that their actions follow them far and wide as well. Keep this in mind when considering how NPCs react to their Persuasion attempts (and Deception, for that matter).
Lastly, I emphasize again to new DM's not to let your players get away with anything just because they rolled high...
Bard: My lovely Queen... Perhaps I could join you in your chambers later for some private consultation over a carafe of fine spirits?
Queen: Guards, have this churl executed for his impudence!
Bard: But.. but... I rolled a 20!