In my last post I left off with a figure showing how the likelihood that a crafter will complete a project requiring multiple successes drops precipitously as DC increases. This is a straightforward result of making multiple rolls with low likelihoods of success. This is realistic in the sense of showing how undertaking a challenging project is uncertain in how long it will take to complete and how much money (how many bad failures) you will need to spend along the way. This is a typical finding in large real-world projects where the true size (GP) and challenge (DC) of the project are not known at the start. A DM wishing to make a new project more realistically challenging might add a random element to the DC, so for example, crafting a clockwork sword robot might be DC30+1d4 where the 1d4 is only rolled after the first attempt. Perhaps what makes Manuals of Golem Crafting so useful is that they spell out exactly how to manage a golem-body building project so it is DC30 and 20000gp in retail cost.
For a project of known DC and skill bonus (i.e., for a fixed target number) there is still a great deal of variation in possible results. The figure below is a histogram showing out of 10,000 trials of a +7 crafter on a DC18 infinite cost project, how many trials were able to complete a given gp in value before failing miserably. Only a very small number of attempts would have suceeded at creating a 200gp project. Students of statistics may recognize this as a geometric distribution, which makes sense since the canonical process for generating geometric distributions is the count of the number of dice a player needs to roll before getting a success. In our case, we are getting this shape from the number of successes rolled before a bad failure with some variation thrown in from the fact that different successes are worth different amounts of craft value.
The mean result is completing only 68gp and the variance is 7,335gp^2. This is a distribution where most efforts don’t get very far but the lucky few can complete big projects. Is that realistic for a worker who isn’t quite comfortable with what he is doing and has to “try his luck” to make progress? I think so. From a different point of view, half of the time, a project to make an item worth 42gp retail will fail (median 41gp), so a craftsman will have to use twice as much raw materials, 32gp (66% of the value), to complete the items on average. This craftsman will on average take about 3 weeks to finish the 48gp item. The rules say earnings are half the crafting checks, but with only 16gp in difference between the raw material cost and retail price, this crafter cannot be getting his 3 weeksx17.5(av. skill check/week)x 0.5(gp/skill check) = 26.25gp out of only 16gp. So what gives? Some might say this just means the rules are an inconsistent mishmash, but I think that the more interesting implication is that, when being practiced to earn wages, the crafters work by taking 10 on the most difficulty item they can make. Crafters who find themselves rolling d20s for their work are probably:
– Have no choice. For example the ship will sink if the patch is not repaired.
– Practice to learn
– Undertaking an ambitious project at the behest of a client/patron
– Did not know it would be so difficult when they started
– Doing it for the inherent value or pleasure of doing it (hobbyist)
Realistically, at very low-skill levels (below 0 net bonus) it is unclear how a crafter could earn a living in the trade at all. A crafter with a -1 net skill bonus supposedly can earn 4.5gp a week by taking 10 on his check, but it is is a stretch to imagine how this person could crediby do so. Below a 0 bonus, taking 10 doesn’t even allow the crafter to aid another crafter, and on his own the -1 crafter can only make items worth 5.4gp more than their raw materials per week if the craft difficulty table is assumed to allow items with a DC of 9. If only DC 5 is available, the -1 crafter can only make items worth 3gp more than the raw mateials. There is no room for the crafter to actually make his supposed earnings. I think it is realistic to assume that noone in Pathfinder is making his living by a skill with less than a 0 bonus, and most of those who are working with a 0 bonus are either apprentices or making very simple items.
All in all, the roll of randomness in crafting doesn’t seem especially unrealistic to me.