Using Skills – Investigation

All right, we’re finally back on track with our ongoing series Using Skills, in which we define and explore each skill in Dungeons & Dragons 5th edition. Last time in this series we took a look at Intimidation. Today we’re looking at Investigation. Enjoy!

Using Skills – Investigation


A scholar pores over a text, surrounded by piles of books, looking for the one clue that will cause everything else to fall into place. The scout inspects a tile in the floor that looks ever so slightly different then the rest. The dwarven foreman taps the cavern wall lightly with his small surveyor hammer, listening to the sound, looking for the best place to begin work on a new tunnel. Investigation is using your powers of deduction to link clues and arrive at a conclusion.

The Player’s Handbook describes it thus: “When you look around for clues and make deductions based on those clues, you make an Intelligence (Investigation) check. You might deduce the location of a hidden object, discern from the appearance of a wound what kind of weapon dealt it, or determine the weakest point in a tunnel that could cause it to collapse. Poring through ancient scrolls in search of a hidden fragment of knowledge might also call for an Intelligence (Investigation) check.” (PHB pg.178)


Normal Usage

Investigation is a broad skill in 5th edition. The main thing to remember is that it specifically represents your ability to use clues to arrive at a conclusion. As we will talk about later, this separates it from Perception in that Perception has more to do with natural sensory/situational awareness. So in order to find an object with Investigation, this object must have some find-able clue to its whereabouts.

Essentially, Investigation is what you use to determine the Why from the What -the What being what you are currently seeing in front of you. A dungeon room filled with destroyed furniture standing in front of you, for example, would require an investigation to figure out why it is the state that it is in. This check might also lead you to clues that you can follow up on, calling for different skill rolls to find hidden objects and other such things.


What it is Not

  • Perception – The Investigation/Perception dichotomy is a tough one, worse in my opinion then the Acrobatics/Athletics one. At the very base, just remember that Investigation is the act of using clues to figure something out while Perception is using your senses. So Perception can find you a cleverly hidden trap door, but Investigation can tell you how it works or how you might open it or disarm it. And if the hidden door is under a rug, investigation might be what leads you to it by seeing clues such as the rug being slightly rumpled leading you to believe it is often moved. The two skills work well together as well, as you can use perception to spot things which might in turn provide clues that let you use Investigation, and vice/versa. Page 178 has a text-box describing finding hidden objects in more detail.


Optional Uses

The following are optional or edge cases for Investigation, and are entirely dependent on the Dungeon Master.

  • Search – In the RAW interpretation of the rules, searching a room basically requires perception. Finding hidden objects, secret spots and other things hidden from view. While investigation might help you along, it is not the go to skill for this. However, in the published D&D adventures Investigation is sometimes called for as an alternative to Perception to find something. As a DM, you might decide to go this route as well, allowing a PC to use their deductive reasoning to find things instead of their natural senses. If you allow this, it is recommended you raise the DC of finding what is hidden with Investigation by 5, so that Perception is still a better option for those trained in it.


Dungeon Master Examples

The following is meant to inspire the Dungeon Master to design with investigation in mind. Remember that Investigation is great as a skill that leads to using other skills, and sometimes vice-versa. When designing your areas, try to have at least a few tell-tale signs of things that require some logic to figure out. Design traps that need to be investigated to disarm, and provide plenty of opportunity to let the PCs inner Sherlock Holmes have some fun.

  • Nested Skill Checks – One thing I do in my games is I try to provide some situations in which a series of skill checks are required. Usually it is just two, but it could be more. For example:
    • Stirge Nest – The PCs come across a part of the cavern with strange slimy splotches decorating the cavern walls. A Nature check will tell you they are territorial stirge marks, and investigation will tell you that they are very fresh.
    • Research – If a PC is searching for a specific piece of information in a library, require a lore check based on the subject (Arcana, History, Nature, Religion) to find the right area to begin searching and an investigation to narrow it from there.
    • Trap – In the event of a trapped hallway, if the PCs are looking for a trap call for a Perception check (if they are not consult their passive perception), and if they find something out of the ordinary describe what they see instead of saying they found a trap. A two inch gap in the floor perhaps, or an odd out of place stone in the wall. Then have them roll Investigation to figure out what it is they’re looking at without needing to physically experiment with it.

That is it for this week, thank you for reading and providing great feedback on this series. Next week we switch it up with Medicine. See you then!

Author: Patrick McGill of 9th Key Press

Content creator for 9th Key Press.

3 thoughts on “Using Skills – Investigation”

  1. As for the “Search” optional use, I’d say it’s the other way: the DC to just happen to see a thing should be higher than to actually look for it.


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