Constructing Target Numbers

    Most games with skills use a Target Number or Difficulty Class, the number you have to roll equal or over to succeed.  These can be a little problematical though, since they are usually just given a general descriptor like "Easy," "Difficult," or "Hard."  Those are pretty subjective measurements.  But if a game doesn't use such broad terms then it tends to have a list of TNs/DCs for each and every skill, which is more helpfully specific, but also more work to look up and keep track of at the table (or stuff into your brain with the rest of the game world).

    I had an idea, what if we tried to keep the best of both with a list of general difficulty components?  These would still be flexible and open to some interpretation, but hopefully specific enough to make it east to remember and adjudicate on the fly.
    Here are some of the things that create difficulty, in my mind, and this list is in no way complete:

• Difficult to comprehend - I think this is what most people first think of when we talk about difficulty, the idea that whatever you're doing is hard to understand all by itself.  If you think my HTML, CSS and JavaScript is hard to follow, stuff like C++ and Assembly Language is even harder.  This element is for things that are hard to do in and of themselves.  Reading is easy, it does not increase the TN/DC - but reading something in a code, or even just a specific group's jargon or accent, may qualify for this.
• Difficult to Track -here by "track" I mean that there is a lot going on, that the action or situation is confusing in part from how many different things you have to be mindful of or react to.  Adding more and more balls you're juggling will trigger this, or fighting in a crowd or mob of people (even just the "flanking" aspect), or texting and driving (which is why you shouldn't do it).  This adds to the difficulty because you have to split your attention.
• Outside Stress -this is kind of like "difficult to track" above, but in a more basic sense.  This adds to the difficulty because there is something related to the problem at hand but not immediately from it.  If your brother was kidnapped and you had to hack a computer for the bad guy to let your brother go, then there is a lot of background stress that is going to make the hacking more difficult.  Even something like the Super Bowl- a regular football game is a challenge, but when it's the last game, the biggest crowd and the best opponents; that makes it even harder.
• Hazard/ Cost of Failure -this increases the difficulty because you know something bad is going to happen to you if you fail.  Walking a tightrope 2 feet above the ground is not as difficult as one 200 feet above the ground - the actions may be the same, but the fear factor makes them noticeably different.
• Incomplete (knowledge, tools, whatever) -here the difficulty comes from the fact that you're missing something important.  It could be physical by not having the right tools, or mental by not having the right understanding or information.
• Unfamiliar/ Unusual/ Uncommon -lastly (for this example) is the difficulty of the unknown.  You may be the best mechanic on Earth, but you're going to have a hard time fixing that alien spaceship.  Even something more subtle like a foreign fighting style, or a culture you have not been exposed to, can increase the difficulty of an action.

    This is relative, so each of these can change based on the character.  One character may be from the city, so milking a cow is "Unfamiliar" to him, another might have grown up on a farm, and so wouldn't have that penalty.  Likewise at a lower level some actions might be "Difficult to comprehend" but would lose that and become commonplace at higher levels.  There is some wiggle room here in determining if each element should apply, it is not a simple one-size-fits-all list.  And, the idea is that it should be explained to the players/ reasoned out, so I would walk the PC through how the TN/DC was created just before they roll (before they are committed to the action if I wanted to be nice, after they were committed to watch the dread as each difficulty increasing element was revealed if I wanted to be mean :).  I think most players would like knowing that know that the difficulty was logically constructed.  And, possibly, they might be able to find a way to negate or remove some of those difficulties once they have them laid out to clearly see.
    Mechanically this is easy, but varies by game.  Basically, each element is worth so many points to the target number total.  The 5e SRD goes by 5s, so each one of these would be worth 5 points to the final TN/DC total.  A game with tighter math, like Fate, might use 1 point per item.  And of course a larger percentile-based system would want 10 or even 15 percent for each.  The goal is to make each item worth the same increase in difficulty so it's easy to remember and create at the table.