You can always brute-force it (one side as two successes)I'm trying to think of solutions to this before I jettison the whole thing and try something else. One is that maybe one of the sides on the attack dice is a critical success and counts as 2 successes? Or explodes? I've no idea how to calculate the odds for that though.
TARGET NUMBER -> | 1 | 2 | 3 | 4 | 5 | 6 |
1 die | 50% | 16.67% | 0% | 0% | 0% | 0% |
2 dice | 75% | 41.67% | 13.89% | 2.78% | 0% | 0% |
3 dice | 87.5% | 62.5% | 33.33% | 12.96% | 3.24% | 0.46% |
4 dice | 93.75% | 77.08% | 52.08% | 28.01% | 11.50% | 3.47% |
5 dice | 96.88% | 86.46% | 67.36% | 44.21% | 23.77% | 10.24% |
6 dice | 98.44% | 92.19% | 78.65% | 58.97% | 37.85% | 20.41% |
One version of that is you roll one or two additional dice, and if you use them to succeed you must narrate a complication.Can you introduce an element that allows the player to add dice to the pool? Perhaps a Push mechanic? Or Assistance from other players? Or situational methods like high ground or flanking or what have you?
This leaves your math unchanged and possibly opens up other avenues of design. Which may be good or bad, depending on your goals.
Adding extra dice would be more intuitive than lowering the TN however. Such a limit and rule would also open other options up like being able to tempt a player with more dice to attempt something.It's a feature not a problem. There solved it for you.
If they want to succeed they need to lower the TN some how, like taking extra time, or getting help.
It's worse than that, it's counterintuitive.To be honest I think that issue is the least of the problems looking at that probability chart, it isn't at all intuitive.
Having a skill of 5 out of six seems really skillful, but if the TN is 3 which sounds low, you only have a 50% chance of success, it moves up to 4, and you are very likely to fail. People with Skill 3, barely have a chance to succeed as TN, even though both sound average.
Adding things like crits explode and stuff like that makes it even less intuitive to understand.
For me, they're at least as intuitive but less susceptible to calculation.Yeah as a very very general rule of thumb rolling twice the number of dice than the target number gives you about a 50/50 chance. Very roughly. Dice pools are defintely one of the least intuitive mechanics when it comes to estimating your odds; I like them though as I enjoy adding and removing dice as modifiers, and throwing a handful of d6s is fun (fireball!) -- I've made quite a few dice pool games.
Some systems make a subset of your dice exploding dice, and the rest ordinary, using different colours. So that you could haveWhat if you added 1 (or 2 or whatever) extra d6(or a d8 or something) of a different colour? That dice has 'effects'. a 6 doubles successes (or lets you re-roll your pool or roll your pool twice or whatever), 2-5 does nothing or adds riders or whatever and maybe a 1 gives you -1 success or something?)
Calculating the mean is a fairly straightforward infinite series, I think - at least that's how I've always done it. But calculating the odds of hitting a given target number seems a bit trickier.The probabilities for exploding dice aren't so formidable, as the most successes you can benefit from are six. So long as you stop rolling when you succeed, and the TN is 1-6, the maths is straightforward. I'm not great at explaining it, but I'll make the table in Excel. The assumption is that a die explodes on a 6, so that a 4-5 is one success, while a 6 is one success + a third of one success (i.e. another 4-5) + etc...) As I'm in transit I'll likely do it over the weekend.
Opposed rolls would probably be the best solution, with the additional benefit that a roll could still be considered successful even if it fails to generate any successes as long as it's larger than the opposing one. You can even treat such rolls as success with complications.