Monday, January 17, 2022

Tracking Systems vs Reliability Systems

If a dragon can breathe fire once every three rounds that's a tracking system.

If a dragon can breathe fire in any round that they roll a 1-3 on a six-sided die, that's a reliability system.



If a spell puts someone out of the fight for 4 rounds, that's a tracking system.

If a spell puts someone out of the fight every round until they save, that's a reliability system.


Depending what you're trying to do, there are good reasons to use either one. Tracking systems and reliability systems often appear side-by-side in the same games, used for different things.

Money in traditional D&D is on a tracking system: you get gold you write down how much, you get mugged by kobolds and lose some you subtract it, you buy a horse you subtract some more, you write down the ups and downs of your bank account, you track it.

This makes sense in especially low-level D&D where the adventure is meant to be the drama of scrambling for resources in an attempt to build up from zero to hero (or at least to Scary Person W/ Expensive Armor). The accumulation of resources is part of the main drama of the early game.

Money in Marvel Super-Heroes (aka FASERIP) is on a reliability system--your character gets a Resources stat at character generation and when you try to buy something you roll that stat vs the item's price stat and see if you can afford it that day.

This makes sense in a genre where the main drama is not the accumulation of resources but rather the idea is that you have this person going along living a non-adventurous life until trouble occurs, and the adventures you go on are interruptions to-, and not necessarily related to-, the business of collecting resources in your daily life. The skrulls might attack on payday, they might attack when you were broke.


In the original DC Heroes game by Mayfair, gadgets had "charges"--like Batman's sleeping gas capsules might have 3 charges, meaning he could use them 3 times per day. This meant if you were playing Batman  you had to keep track of a lot of things.

In the 2nd edition of DC Heroes they changed it so gadgets instead had "reliability numbers"--if you rolled below a certain number when using a given gadget, it was jammed or out of ammo and you couldn't use it again until you addressed the situation. A bad reliability result on Batman's sleeping-gas capsules would indicate he hadn't packed them that day (and instead presumably packed something else), or they'd gone stale from not being used, etc. A bad reliability result on a gun would mean it was literally out of ammunition or had jammed (important for the GM to decide which in this game, but presumably in a more gun-heavy genre than super-heroes the mechanic itself would specify which).

This 2nd edition mechanic combined the use of a reliability system with another mechanic, whereby the "reliability roll" was actually just part of the normal to-hit roll associated with the thing.


A get-out-of-jail-free card is a tracking system. You have the ability to escape a given danger or you don't, you know in advance, you can use it a known number of times (one per card).

A saving throw is a reliability system. You don't know how many times it'll work or even whether it'll work, you just know the odds that it'll work.


Traditional (non-RPG) card games almost always involve an element of tracking but can also involve reliability.

Traditional (non-RPG) dice games almost always involve an element of reliability but dice can also be used for tracking.


Tracking systems often, but not always, involve a species of resource management (for an example where they don't: it's debatable whether it's helpful to call the dragon's-breath example above a kind of "resource management").


Vancian magic (a spell can be used x times per day) is a tracking system and you can see why many people prefer it to a reliability system. Being limited in how many times a day you can cast a thing can be annoying but in many circumstances it's less annoying than the reliability-system version: taking your wizard's turn to cast a spell and then it does nothing (this may be why so many early edition spells have no save or a save that only limits the effect: the magic-user at least gets to use their turn to do something).

A wizard on a Vancian system who is out of spells at least knows they're out of spells and can start thinking what to do in any given round from there rather than taking turns all about failing over and over.


There are lots of reasons to use one or the other kind of system in a given situation, but that would require making the article longer than most peoples' attention span, so I'll stop there for now.

The main thing is: if tracking something in a game gets annoying, you might want to switch to a reliability system, and if a reliability system gets annoying, you might want to switch to a tracking system.



maasenstodt said...

This seems like an obvious distinction but, as is often the case, it's helpful to spell out what is plainly true.

Thanks for the post!

Simon Tsevelev said...

Just what I like about your posts - simple, precise, helpful.

Benjamin Cusack said...

These seem related to input vs output, like using something in response or rolling a saving throw is caused by outside input on the player character, whereas output would be using a spell or item to affect a situation.
I think there is a lot to learn from boardgames on this front, with really complex systems present in some games, especially German style games, there is a beautiful system hidden under many layers of choices you have to understand and plan.
So if you use something and it is the wrong time or you fumble, it is really punishing, like a lot of spells in lots of RPGs.
That is one reason I dislike super specific spells in systems that limit magic to a certain amount, it makes players hesitate to branch out or do something less useful or powerful.
To this end, I have several ideas, the core of which is something I have termed stomach magic; essentially the player is given magic spells, which they track on each use. When you use a spell, it goes into a stomach, which releases all spells once full. The stomach is full when all the spells you have are put into it, or when you hit certain thresholds, depending on the patron of your magic.
The other part of this is that patrons require you to have spells that constitute payment. A demon might make a player have a spell that kills someone innocent, or a blood mage might have a spell that deals them damage. This means players can cast spells more freely, but must cast this "bad" spell to retrieve all their used ones.
This means a player can go wild, and do powerful things, but the cost adds up, and if it is life or age or warts or dementia, this makes the magic user become more and more interesting, and they balance magic and their other resources.
As they level, they might get more and more of these bad spells alongside good spells.
This does tracking in a better way than vancian, because players have more stake in using things, because they can get them back, but the cost is now a concern, not wasted dead time with no spells.
I wonder what other think about this system, and sooner than later I will be writing alot more on it, so let me know what you think!

Zak Sabbath said...


when you have it worked out in detail make a blog entry and remind me