Rules that back source

[Callan S.]

This is a condensation of the 'Rules that outsource' thread. I'd give a direct link, but that might give the idea that you have to read through it before tucking into this one.

As was pointed out in that thread (by Valamir), most gaming groups don't want to do everything themselves. It's like a company that doesn't want to do its own catering, so it looks around for a catering company, decide which one they like and use it/outsource their catering needs to them. With the gaming group they might not want to design or make up as they go, a combat system. So they look around the books from various publishing companies, and find one that fills their needs. They outsource to this book to fill their needs.

This post is about framing and discussing the problem with rules (and info) that back source. What that involves is someone out sourcing to these rules to achieve a certain goal. Back sourcing occurs when the rules don't take on the work of achieving that goal themselves, they instead hand the work (a lot of it or even all of it) back to the person who out sourced to these rules to begin with, on the sly.

Some examples, starting with an information back source.
* According to Monte Cooks review, the 3.5 edition of the DMG has the stats for NPC's, but just a gold value for equipment held. Unlike the 3.0 edition, to reference these quick NPC's, you need to take the time to determine their equipment (in an equipment centric system). Even if your happy to make a rough guess at equipment, you could have guessed stats as well (as they are the least complicated component). Either way, it fills space posing as information, but back sources to the user to actually obtain anything useful from it.

* The palladium system. Stats under 17 (or 16 in some books) have no modifiers or any significant game effect. The system then randomly generates characters who typically fall well below this mark. It also provides physical skills which (with significant book work) boost them, but typically can not do so enough to get them to 17 regularly. This leaves the majority of stats apparently 'handled' by the system, but really back source to the user/GM to determine what their effects are.

* Palladium system again. Skills are each given varying percentages, with a varying bonus per level. However, though these numbers lengthen character gen, and are quite particular, its clear failure in mundane tasks like driving a car are certain, unless GM discretion/back sourcing is used. Clearly circumstance must be taken into account, for things like cooking in a well stocked kitchen, but although the system is particular about the percentages, this is back sourced to the GM.

It's difficult to give more solid examples. Most are observable from really engaging a system. A light skim of them doesn't usually pierce the smoke screen of these rules.

Some generalised examples, now:
* Having complicated formula, yet the user/GM has so much control over the inputs to that formula that he controls the result. If the formula is X + Y = Z, and you control X and Y, then you control Z. However, if the system says it produced/controlled Z, the GM is absolved of responsibility for the result. Actually, this is an attractant for some GM's. An example are the honour rules in hack master, which at their core are driven by the GM's personal bias and opinion. However, it can end up being passed off as a result of the system (unwittingly or not). Clearly the GM doesn't have a problem with the back sourcing here…as a consumer he may even encourage designs like this with his future purchases. However, the problem here is that accountability is screwed. The system says its responsible, but the systems actual design makes the GM responsible. Dysfunction is inevitable.

* Having small formula/modifiers attached to textual directions for use. An general example might be cowardice gives a -2 penalty. What cowardice actually is, is left up to the user. They have to go through the workload of determining if it fits the creative agenda, the social contract, the current scene, the system balance, etc, before they apply it. A hell of a lot of back sourcing. The system lists -2 next to the word cowardice and calls it content, when it's really only offered a modifier that could easily be guessed (your already guessing all those other things, after all). In addition, this can again lead to accountability being screwed, with the GM stipulating that fear exists in PC 1 so this modifier comes into play. This uncomfortably misses the fact it was the GM deciding fear existed, not the system. Confusing his own opinion with the system telling him something has to happen. Dysfunction is inevitable.

* Poor system wording leading to GM opinion/system assertion mix ups. This leads to the GM equivalent of 'My guy' phenomena. In this case it's 'This happens because of events in the game world. So this isn't me doing it, it’s the world'. The very same game world controlled by that GM! The wording in systems typically encourages this 'If X is happening, this other thing should happen', rather than 'If the GM determines X has happened, he should decide if this other thing should happen'. Some might think its obvious that the GM is determining things, and thus isn't needed. But this fact slips away all too easily (especially during suspension of disbelief), and with it correct responsibility slips away too.

Further, I've heard the line 'Look, if you just make a reasonable decision, then events work out as the game would have it' in various places, including the forge. Presumably an echo of the texts in RPG's. As if a 'reasonable' decision means your consulting some universally agreed/group agreed decision on what reasonable is. And thus events in the game based on reasonable decision are just a product of the game, not the GM's personal opinion or bias's. This is just shifting responsibility again, with its inherent problems. It would be nice if there was some universal decision on what reasonable is, or if one could be perfectly in touch with a group decision on what reasonable is. There isn't and you can't. But time and again it seems a tradition (as shoving a combat section into any new RPG is) to shift responsibility off the GM. I guess it’s a faint hope that the group can outsource almost everything, add reasonable decisions, stir liberally and everything will be alright. Have you ever had a dream so real, Neo?


That's the end of the examples. These are lazy rules/texts, bordering on miss leading advertising. Products shouldn't say they will help you achieve a goal, then leave you to achieve it by yourself. And as described they also lead to dysfunction in the group.

I'm not sure if this'll get much more response than it previously has. Posts where someone has come up with a weird random math equation and now wants to know what they could do with it, seem to be regularly engaged. Still, this post needs some discussion. Do you believe some all or none of the above assertions? If you believe some or all to be true, has there been any work to fix it currently in the industry? What sort of work could be done?

[M. J. Young]

First, to make certain we're all on the same page, let me make some statements in the expectation and hope that you agree.[list=1][*]Backsourcing is inevitable.

No game book can cover everything that might ever arise in play; at some point the book is going to have to say, "Use your best judgment based on what you've read here."

[*]Backsourcing is not necessarily a bad thing; it has positive features.

Multiverser, for example, maintains that anything you can imagine can be included in the game, including that any skill, equipment, character, setting, or even system from another game can be incorporated as part of play. To do that, there is a tremendous amount of generalizing--skills which magically create fire, skills which psionically create cold, physical attacks which do special categories of damage, spaceship systems not otherwise covered--and then give guidelines for the referee to work out the details of any specific item he wants to include. This gives the game a trememdous amount of flexibility, making it possible to achieve the stated goals in a game book considerably shorter than the Encyclopedia Brittanica (which also attempts to cover everything).

[*]The problem you're identifying is specifically rules that claim they are providing clear answers to any question (such that anyone who read the rules would arrive at the same answer) while in practice putting the problem back in the hands of the referee such that he is going to have to answer the question himself, and sixty different referees could derive eighty different answers.[/list:o]
That said, I agree.

However, I have a caveat to raise.

Having complicated formula, yet the user/GM has so much control over the inputs to that formula that he controls the result. If the formula is X + Y = Z, and you control X and Y, then you control Z. However, if the system says it produced/controlled Z, the GM is absolved of responsibility for the result.

I see your point; on the other had, we do something very like that for character design in Multiverser, and I think it's significant. Let me describe the example.

Question: how much damage can the character take before it is dead?

Answer: add the character's stamina, resistance, density, and will power attributes, and divide by four to determine damage value. (There's more to what that means, but this suffices for the example.)

Of course, the character's stamina, resistance, density, and will power are all variables determined entirely by the referee; so in that sense, the referee sets the damage value by controling the underlying stats.


Yet the process provides a useful guideline. After all, the referee will have understood the game meaning of those four stats; he'll understand that setting those underlying numbers in certain places will have very particular meaning in relation to what sort of character/creature he's creating. A high stamina means a healthy, robust character; a high will power means a stubborn one. It may be easier to define the character in terms of these identifiable numbers than to merely tag a random damage value to it; the damage value at least will make sense based on the nature of the creature, and the nature of the creature will make some sense based on its damage value.

The method cuts both ways, as well. If for some reason I want a damage value in a particular range, the system forces me as referee to provide a rational basis for that number. Is there some basis for suggesting that this particular creature has a significantly higher density than normal humans? (Density is not terribly flexible for humans under the system, and tends to weigh down damage value improvement.) I need to make it tough, or stubborn, or resistant, or some combination of those, to get that damage value, and that may force me to consider why it is as it is. Similarly, if I'm trying to create a creature with an extremely high resistance (e.g., because it is very useful against many forms of magic, among other things) but do not want it to have a high damage value, I may have to consider where its weaknesses lie.

So a formula which derives an outcome from input variables determined by the referee may still have significant value, if it makes the system easier to use or otherwise enhances play such as through creating consistency.

--M. J. Young

[Ian Charvill]

This post is about framing and discussing the problem with rules (and info) that back source. What that involves is someone out sourcing to these rules to achieve a certain goal. Back sourcing occurs when the rules don't take on the work of achieving that goal themselves, they instead hand the work (a lot of it or even all of it) back to the person who out sourced to these rules to begin with, on the sly.

If we accept the priciple that events only occur within a roleplaying game as the result of consensus among the players - i.e. the Lumpley Principle) - how can any rule in a roleplaying game not backsource?

I'm suggesting that it is literally impossible - not unlikely, not unusual, just impossible - for a rule in a roleplaying game not to backsource.

[I'd say that historically, RPG rulesets have been good at letting GMs know that ultimately responsibility lies with them and they're free to change the rules as needs be; too, historically, rulesets have been less good at letting players know that this is going on (admittedly here, this presumes levels of naivity on the players part that I've never seen in actual play).]

Therefore, I'd limit considerations of backsourcing as a negative quality solely to background material which present itself as being complete when it's only partial.  Frex, a map of the city of Nylador which only shows the merchant's quarter (the D&D stat example might also pertain, depending on how the stats are presented in the book).

[Itse]

Yeah, good point Noon.

Backsourcing makes many rules just pointless. A list which says "fear -2, elevated position +3, hunger -1, longer weapon +1 or +2, wounded -3, fighting for survival +2" is useless. The exact same result is achieved by stating something simple like "the GM should try to consider negative factors like fear, hunger and wounds and compare that to positive factors like will to survive and possible a weapon with a long reach. After that, a GM may modify the roll by 5 to either direction". Actually this option is better, since now instead of little bits of info the GM is given a straightforward guideline on how much he should let the circumstances affect the rolls in general.

MJ wrote:

So a formula which derives an outcome from input variables determined by the referee may still have significant value, if it makes the system easier to use or otherwise enhances play such as through creating consistency.

Personally, I never use those rules. They just tend to slow things down. After I've figured out what's the range of the values and what are the typical numbers, I just come up with the results according to it, since it's much faster. I find this to make games both more fun and more realistic. The formulas never really work.

[Ian Charvill]

Backsourcing makes many rules just pointless. A list which says "fear -2, elevated position +3, hunger -1, longer weapon +1 or +2, wounded -3, fighting for survival +2" is useless. The exact same result is achieved by stating something simple like "the GM should try to consider negative factors like fear, hunger and wounds and compare that to positive factors like will to survive and possible a weapon with a long reach. After that, a GM may modify the roll by 5 to either direction". Actually this option is better, since now instead of little bits of info the GM is given a straightforward guideline on how much he should let the circumstances affect the rolls in general.

With respect, general rules like that are tremendously difficult to impliment without examples.  And what would a list of examples look like? Something like "fear -2, elevated position +3, hunger -1, longer weapon +1 or +2, wounded -3, fighting for survival +2" perhaps?

[Callan S.]

M. J. Young: Some responses to your statements, to give some common ground.
1. No, I don't believe some back sourcing is inevitable as in always needed. This is primarily because I believe you can roleplay in GM'less systems like fighting fantasy and things like warhammer quest.
However, in the typical RPG designs which have a GM, yes, I agree some back sourcing is inevitable. We'll stick with typical RPG designs, to keep things simple.

2. I forgot to port over from the previous thread that yes, some back sourcing is fine. In small doses, its probably one of the main attracting features of this hobby. But I'd suggest it being an attractive is one reason why, when too much is used, it fails to be identified as a problem.

However, the basic idea of out sourcing is that you hand over responsibility to someone else's work (the RPG's author). The more his rules designs back source, the less of a hand over of responsibility it was. I'd actually strongly suggest that it’s a geometric reduction of hand over, for each notch you turn up the dial (ie a careless design that turns up the dial a notch or two has far more effect on this hand over, than you might think a notch or two would).

3. Yes, its about elements of rules putting decision making back in the GM's hands. Also about doing it dishonestly in the design (suggesting there is no hand over, as everyone who is 'reasonable' would read this bit of back sourcing the same way). And as said before, its about doing this more than a bit, until it invalidates the existence of the rule.

On your caveat: Your formula does sound highly variable and back sourcing highly. But your forgetting one element of it…permanency. I imagine that in your system PC's, for example, don't metamorph all the time. Given the breadth of what that system is supposed to cover, I imagine they could, but typically they wouldn't. The back sourcing dial is turned down, since the GM or whoever can not simply screw with the number at any time and produce the result they want.

However, the reason behind why PC stats don't change every minute on GM whim is mostly a matter of gaming tradition, book guidelines (which back source themselves) and group preference. It's generally not rules enforced in any book.

As for NPC's

After all, the referee will have understood the game meaning of those four stats; he'll understand that setting those underlying numbers in certain places will have very particular meaning in relation to what sort of character/creature he's creating.

I think this means it back sources back to creative agenda or whatever arrangements of the group. The more elements the formula calls on, the more places there are that are accountable to creative agenda. The more bits that could be questioned if they are cranked up. This helps the back sourcing to creative agenda, which helps turn down the dial a little. But I'd say it's still turned up.

The method cuts both ways, as well. If for some reason I want a damage value in a particular range, the system forces me as referee to provide a rational basis for that number. Is there some basis for suggesting that this particular creature has a significantly higher density than normal humans?

I'm not sure how you mean the system forces you to do this. One way a system can force you to justify your choices is to make each stat point buy, with a fixed amount of points. Another is the same but the amount of points isn't fixed, its policed by creative agenda (still back sourcing though, to X degree).

So a formula which derives an outcome from input variables determined by the referee may still have significant value, if it makes the system easier to use or otherwise enhances play such as through creating consistency.

As I said, I think such a formula help in the way it back sources to the user. It gives various elements for creative agenda to evaluate  (what, he had all his stats pumped up…that's just wrong! Etc). Also I think the wording of such a thing is important, something like 'the GM assigns stats to the creature that are realistic' is bollocks, while 'the GM assigns stats at will, his goal is to try and be realistic' is healthy, pointing to where the responsibility really is. The former is a real problem, because if the creative agenda polices the GM, but the system says he just uses 'reasonable' estimates of 'realism', then it shifts responsibility onto that…which screws up group arrangements for a good game.

Ian Charvill: Back sourcing is something that happens before the Lumpley Principle, as I understand it, applies. For example, the system generates 6 damage, but the GM then goes on to say it was 4 damage and the players nod and write it down. What the GM said isn't important, it's important that the system justified its existence by providing a result that the GM can use (how he see's fit, like changing it, whatever), and the result isn't entirely a product of his desires (which would happen if he has full control over the inputs). When he has absolute control like that, you may as well free form, the system is a waste of time and it's miss leading (it misplaces responsibility for play…at least freeform doesn't).

[I'd say that historically, RPG rulesets have been good at letting GMs know that ultimately responsibility lies with them and they're free to change the rules as needs be; too, historically, rulesets have been less good at letting players know that this is going on (admittedly here, this presumes levels of naivity on the players part that I've never seen in actual play).]  

I'd say these systems also back source to creative agenda and other group arrangements. The players do a lot of the policing of this. And when you have a system which says the GM isn't in control when really he is…their policing is flucked up.

I'd also say I think a lot of systems can leave the unwary GM to believe the same hype it gives to the players. Even more dysfunction and denial of responsibility.

Itse: Some of those examples you give can be built into the system, but get left to best judgement for some reason. Like 'wounded -3', its quite easy to define when this happens mechanically (eg, when you've lost 5 HP or whatever). However, I have seen failure on this. Palladium again, stating that if a mage suffers damage while casting a spell, the spell fails. That was it. So what is damage? One point? Mages in that system start out with HP and SDC that total about 20 or 25…one point is nothing in comparison to that.

It's interesting how you say you don't use rules like that mentioned in MJ's post. Did you perceive that you had so much influence and that you might as well take over entirely?

Ian Charvill, again on your latter reply to Itse:

With respect, general rules like that are tremendously difficult to impliment without examples.

I'm curious as to why it's tremendously difficult. D20's 'GM's best friend' rule of adding +2/-2 for circumstances ask for something similar (while those things from above that it does includes modifiers for are usually codified into the system so much that no judgement call is needed).

Examples like hunger or fighting for survival are huge judgement calls. The difference between 'Weve given you one word as a guideline for when to add this particular number' and  'just make it up yourself, within these numerical limits' is a thin one. With such a thin difference, why is there tremendous difficulty with one of these methods? :)

[Ian Charvill]

Noon,

The way I see it, the system has no credibility except that people assign credibility to it.  In other words, for the GM to be able to shift the damage from 6 to 4 because he decides the wind in strong enough to interfere with the arrows or whatever on a judgement call, then the players need to apportion him that power.  He can't do that because the system says so, he can do that because the players are assigning credibility to him.  Furthermore, he doesn't gain that credibility because the system apportions it to him; he gains it because the players apportion it to him.  The rules propose but the group disposes.

Now, if you're saying that the text is misleading the GM into thinking the rules are making a judgment when he is making the judgment, that charge may have some merit.  I'd suggest the best way to settle that is simply to quote the misleading text from one of the game systems you're thinking about.

The reason why I think the +/-2 circumstance bonus, without examples, is troubling because: what will the text say?  Assign a +2 bonus if cicumstances are advantageous to the attacker.  What's advantageous enough?

5'10" fighter vs 5'8" fighter - is that enough for a bonus; what about 5'2" vs 5'10".  What about sword vs short sword?  Sword vs dagger?  I'm on a table, does that give be a bonus due to height.  What about a stool?  A horse?

I can see an argument in favour of making the players aware that if the GM is applying a bonus or penalty then thay have a made a judgement call; but I don't see how making the grounds for the bonus or penalty vague does anything to prevent dysfunctional play - i.e. I don't see how making the conditions for the bonus or penalty vague would act as a better regulator of abusive use of power by the GM.

[Valamir]

I think, Callan, that you're running the risk of overexaggerating the issue.

From my perspective the issue is not "is back sourceing bad", or even "is too much backsourcing bad", but rather whether the game design is forthright and specific about it.

I think blanket statements like "The GM is always right", or "The GM controls everything" are where the backsourcing becomes disingenuous.  Such rules allow the GM to use "Buts its in the rules" as a justification for every whim, and leave the players with little option but to rebel or quit playing.

Such rules I think circumvent the intention behind the Lumpley principle in a very negative way.  The players apportion credibility as part of their social contract, but rules like the above seek to bypass that apportionment and give the GM more credibility than the player's had intended to alot to him.  This creates a divergence in the level of authority the GM claims vs. the level of authority the players granted, and I think is where the backsourceing becomes a negative.

Instead I think games should rely on backsourcing, because the alternative is 500 page tomes of rules, or situations so narrow as to be describable in fewer.  But each instance of backsourcing should be made individually explicit with guidelines and sufficient "game design notes" to give players the feel of the spirit of the law as well as the letter.

[Callan S.]

Noon,

The way I see it, the system has no credibility except that people assign credibility to it.  In other words, for the GM to be able to shift the damage from 6 to 4 because he decides the wind in strong enough to interfere with the arrows or whatever on a judgement call, then the players need to apportion him that power.  He can't do that because the system says so, he can do that because the players are assigning credibility to him.  Furthermore, he doesn't gain that credibility because the system apportions it to him; he gains it because the players apportion it to him.  The rules propose but the group disposes.

You outsource before you apply credibility...you can't apply crediblity to a result you don't have yet (and if you try to, it suggests you don't really want to outsource). What is important is that the GM gets a result from the system that makes it worth outsourcing to that system in the first place. What makes the result worthless is when its so open to influence by the GM that using the system was pointless, the result is going to be what they want regardless. Imagine outsourcing to a tarot deck, the GM picks one and then 'reading it', says what the in game result is.

Actually, the tarot deck is a healthy option, because its painfully obvious the GM is using it as inspiration, he isn't outsourcing to it for a result. However, imagine rules that dress as rules, but play as tarot cards?

Now, if you're saying that the text is misleading the GM into thinking the rules are making a judgment when he is making the judgment, that charge may have some merit.  I'd suggest the best way to settle that is simply to quote the misleading text from one of the game systems you're thinking about.

*Grabbing TROS because its the closest*
>>> 'Gift: Beauty of legend *snip* Any rolls that involve beauty (many social or entertainment skills, for example) are made at +1 dice.

This isn't an example of the back sourcing dial turned up really high, but it's turned up. The skill guideline helps turn that dial down somewhat, but what is beauty?

Tis in the eye of the beholder. Tis in the eye of the RPG user. Tis back sourcing. And the old 'Oh, but if the GM makes a reasonable choice, it'll work out JUST as the game designer intended' smoke screen doesn't fix this.

Note: As I said, this isn't an example of the dial turned up high. This is just an example with the dial turned up to some degree.

The reason why I think the +/-2 circumstance bonus, without examples, is troubling because: what will the text say?  Assign a +2 bonus if cicumstances are advantageous to the attacker.  What's advantageous enough?

5'10" fighter vs 5'8" fighter - is that enough for a bonus; what about 5'2" vs 5'10".  What about sword vs short sword?  Sword vs dagger?  I'm on a table, does that give be a bonus due to height.  What about a stool?  A horse?

Previously you wrote that a one word example is adequate. Like 'cowardice: -2'. Why this isn't just as troubling intrigues me. Questions come to my mind...do all cowards all react at minus two, when does cowardice apply? When you see a rat, a hippo, a dragon?

In fact, the range of questions reflects those you ask, in diversity. Perhaps because one word examples don't aid judgement much more than thin air does.

I can see an argument in favour of making the players aware that if the GM is applying a bonus or penalty then thay have a made a judgement call; but I don't see how making the grounds for the bonus or penalty vague does anything to prevent dysfunctional play - i.e. I don't see how making the conditions for the bonus or penalty vague would act as a better regulator of abusive use of power by the GM.

It makes it dead clear that responsiblity is at the GM's feet, not at the books. 'Cowardice: -2' suggests the book had something to do with it, while 'The GM makes up a modifier out of thin air, between -2 and +2' doesn't.

A game with no examples will probably run better than one with missplaced responsiblity.

[Callan S.]

Valamir: True, the system keeping the user honestly informed of whats going on really helps. But keep in mind that even with a honest system, if the back source dial is turned up, there's not much difference between it and freeform except the latter is faster and simpler.

Still, this might be up to the end user to decide. If well informed, they can choose themselves, though I'd be concerned that you don't really know how the rules run/would say how they run untill you own the book.

Perhaps I'm showing my bias against really high back sourcing. I get the feeling such a thing is close to freeform, but has the appearance of rules enough to give 'dutch courage' to people who otherwise wouldn't freeform.  The book doesn't influence their freeform much at all, they could do the same without it. But like someone who needs to be drunk before they can kareoke (sp?), its dutch courage to do what they could have done anyway. Yeah, I'd say I was biased! :)

[Ian Charvill]

The general goes to the oracle before the battle.  The oracle tells him the birds are flying west.  It is not auspiscious.  The general goes down to his army and orders a retreat.

For me, the general is solely responsible for the retreat.  For the general to argue the oracle had anything to do with it would be, for me, and act of moral and intellectual cowardice.

The general chose to consult the oracle; he chose to follow the advice.

Similarly, the act of referring to rules as well as the act of following them both are under the absolute control of the GM.  Referencing the rules apportions them credibility.

[Itse]

Ian Charvill wrote:

With respect, general rules like that are tremendously difficult to impliment without examples. And what would a list of examples look like? Something like "fear -2, elevated position +3, hunger -1, longer weapon +1 or +2, wounded -3, fighting for survival +2" perhaps?

Noon pretty much covered this, but I'll mention one thing. One problem I see with these kinds of lists is they are often written in a way which actually limits the GM: "fear -2" says that fear will either cause a -2 modifier or it will not. It doesn't leave an option for a -1 modifier, for just a little fear, and not for a -3 modifier for a really scary thing. Of course, a smart GM is not troubled with details like this, but it goes to show how pointless the list is to start with. Also, there is a difference between an example and a rule.

Noon asked:

It's interesting how you say you don't use rules like that mentioned in MJ's post. Did you perceive that you had so much influence and that you might as well take over entirely?

Pretty much. Also, just coming up with the modifiers make the game run much faster and smoother. I trust my interpretation of the situations effect on the characters to be at least as good as it would be guided by a system. To me this is self evident, since I'm familiar with the characters and I'm actually there. (Yes, I'm very confident as a GM. That's one of the reasons I mostly don't bother with rules-heavy systems. I just don't need preset game mechanics that much.)

[M. J. Young]

I'm getting thrown in a couple places by what might be called "non-standard" uses of words.

System: everything used by the players to determine what happens in the shared imaginary space.

Rules: all codified or otherwise openly stated means which the players have overtly agreed are part of the system.

Credibility: the degree to which any real person involved in play is permitted to define events in the shared imaginary space.

Authority: the degree to which rules can be explicitly or implicitly cited to challenge or support the credibility of decisions.

If the rules say six dice of damage and the referee says four, and the way the group plays the game the referee has the credibility to make that decision, then the system has generated the result that there are four dice of damage. In this case, the referee's ability to redefine the damage is inherently part of the system, despite not being codified in the rules.

If the referee has reduced six dice of damage to four, and the player making the attack says, "but the book says I get six", that is a challenge to the credibility of the referee through appeal to the authority of the rules. Somewhere in the unwritten social contract will be the answer to the question of whether the referee has the credibility to make that reduction or whether he is bound by the rules. This, too, is part of the system. In some game groups, the authority of the rules is sufficient that the referee must yield to the them if they are presented. In other groups, the credibility of the referee extends to having final interpretation on application of the rules, such that he can go so far as to say "we're not using that rule" (whether or not so bluntly as that), or that he can change the rules as suits the situation (as illusionist and participationist referees often do) to reach the desired outcome.

Callan, I think to some degree you see the rules as the totality of the system having credibility in themselves. They cannot be either of these. They cannot have credibility in themselves because they cannot watch play and respond by speaking into the shared imaginary space without passing through one of the live persons involved in play--usually the referee. They authority of the rules is inherently limited by the understanding (and thus the interpretation and application) of whatever player has the credibility to determine what the rules mean and how they apply in play. They cannot be the totality of the system because the system must include the determination of who has credibility to make that interpretation, at the very least.

This may be the point at which backsourcing is most clearly seen as unavoidable. If the rules say, "the referee will apply these rules to play, and have final authority as to all in-play events", they have backsourced that aspect of credibility to a designated player. They have equally backsourced that aspect of credibility if they state that the group should agree regarding the application of the rules. If they make no statement on that point, they fail to answer a critical question (who decides how and when the rules apply), and so implicitly backsource the question to the group. The one essential aspect of rules is that they are dependent on one or more persons bridging between the rules and the shared imaginary space, and thus they must backsource that much to the group or some portion thereof in order to be part of play at all.

--M. J. Young

[Ian Charvill]

The problem with the lists example is that I'm unaware - perhaps blissfully so - of any written rules that do what people seem to be accusing them of.  Some examples.

HeroQuest has extensive lists of resistances - but they're clearly sample resistances.  Says so at the top of the list.

D20 then.  Bunch of tables.  "Combat Modifiers" section stretches three or four pages.  But "Your GM judges what bonuses and penalties apply, using [the following tables] as guides".  So pretty clear where the buck stops.

Maybe this is a historical thing, and I'm being too modern.

GURPS, 3rd ed.  OK - tables coming out of the kazoo.  Modifiers for everything from fright (p.93) to fights p.201 to bribing and informant.  Even a rule headed Use your common sense.  Unfortunately, there's also buck stops here text aplenty.  Frex, "In any question of rules, the GM's word is law" - their italics.  The section goes on to say the GM has the final word in what rules are used and how disputes are settled.  There are lots of imprecations to keep things fun for the players - but in the end "a good player accepts the GM's judgement when it is made".

So I'm just not seeing systems that give a list of modifiers without making it clear that the GM has the right to use them as they see fit.  I'm not seeing sleight-of-hand backsourcing.  Maybe I'm missing important sysems that do just that.

[John Kim]

So I'm just not seeing systems that give a list of modifiers without making it clear that the GM has the right to use them as they see fit.  I'm not seeing sleight-of-hand backsourcing.  Maybe I'm missing important sysems that do just that.

While there is no black-and-white dividing line, I see a qualitative difference between how GURPS handles things and how Hero Wars does.  To me, the litmus test for "back-sourcing" would be:  if you have the complete game mechanics for something worked out -- like a combat, for example -- how different will it play out depending on who the GM is?  i.e. Suppose one PC is fighting another PC.  In a low-backsource system, the two players could easily do it without needing a GM.  In a high-backsource system, the results could vary considerably depending on who was GMing and how they made various judgement calls.  

Now, low-backsourcing typically only works for a limited set of conditions.  i.e. If in a GURPS combat you decide that everyone is fighting waist-deep in popcorn with butter covering everything, then there are a bunch of judgement calls to make about how this affects the combat mechanics.  But within "normal" combat conditions this isn't necessary.  

But I think there is still a real distinction between low-backsourcing (i.e. fewer and/or more obvious judgement calls) and high-backsourcing (i.e. more and/or more variable judgement calls).