Upgrade your account to a Community Supporter account and remove most of the site ads.
Rocket your D&D 5E and Level Up: Advanced 5E games into space! Alpha Star Magazine Is Launching... Right Now!

Reply to thread

Message: <blockquote data-quote="pemerton" data-source="post: 6364998" data-attributes="member: 42582">Other than skills and rituals, you mean?4e is based around much higher chances of success than 2 in 5 (which is what Quickleaf indicated upthread: +2 bonus vs DC 15). Most of the checks in a skill challenge will be Medium, and a character who is proficient in a skill, or has a good stat, should succeed at a Medium check around 2/3 of the time. If the character is proficient and has a good stat that success rate may be closer to 9 in 10. And that's before factoring in items, power bonuses etc.Also, once the number of success required gets beyond 6 before 3 failures, 4e (post-Essentials) has the somewhat ad hoc system of "advantages" - basically, ways to mitigate adverse odds by column-shifting DCs or undoing failures.Here is the "7 before 3" maths for a success chance of 3 in 4, which is not a bad generalisation for the bare bones of 4e:The chances of 7 successes in a row is 3^7 over 4^7. This = 2187 in 16384.The chance of 7 successes and 1 failure is 3^7 * 1 [for the failure] * 7 [because there are 7 "slots" into which the failure might fall, before the final success], all over 4^8. Which equals 2187*7 = 15309 in 65536.The chance of 7 successes and 2 failures is 3^7 * 1^2 [for the 2 failures] * [the number of ways of allocating 2 "slots" out of 8 to failures, = 8!/6!2! = 8*7/2 = 28]. So 2187 * 1 * 28 = 61236 , all over 4^9 = 262144.Adding all these together over a common denominator:(2187*16 + 15309*4 + 61236)/262144= (34922+ 61236 + 61236)/262144 = 157394/262144which is just a tiny bit more than 60%.In practice, in 4e, I think the chance tends to be higher because of advantages, the ability to gain bonuses that lift the chance above 3/4, etc.To get a 3/4 success chance in 5e (ie succeed on a 6 or better on d20), assuming a typical bonus of around +2, is going to require DCs of 8. Even if DCs are 10, the chances of success for characters with a +2 bonus (ie succeed on 8 or better on d20) is going to drop markedly.If we treat a chance of 13/20 as a 2/3 chance (because I'm not going to do maths that involves 13^7!), then we get the following:The chances of 7 successes in a row is 2^7 over 3^7. This = 128 in 2187.The chance of 7 successes and 1 failure is 2^7 * 1 [for the failure] * 7 [because there are 7 "slots" into which the failure might fall, before the final success], all over 3^8. Which equals 128*7 = 896 in 6561.The chance of 7 successes and 2 failures is 2^7 * 1^2 [for the 2 failures] * [the number of ways of allocating 2 "slots" out of 8 to failures, = 8!/6!2! = 8*7/2 = 28]. So 128 * 1 * 28 =  3584, all over 3^9 = 19683.Adding all these together over a common denominator:(128*9 + 896*3 + 3584)/19683= (1152+ 2688+ 3584)/19683 = 7424/19683which is between 37% and 38%.I don't think that's very viable, myself. It also shows that, with these sorts of numbers, the presence or absence of Guidance will make a very big difference to success rates.</blockquote>

Verification