Skip to main content
Role-playing Games

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

Required fields*

11
  • 1
    \$\begingroup\$ "If we figure that the typical hit chance is close to 50%": why? It depends on attack bonus and target's AC, doesn't it? \$\endgroup\$ Commented Mar 7, 2023 at 8:53
  • 3
    \$\begingroup\$ To first-order this is accounted for by the margin of success: every +1/-1 difference in attack bonus and AC produces 1 more or fewer hit per 20 attacks as desired. But as hit chance gets far from 50% then you start to see more higher-order error due to the target standard deviation and normality decreasing, going deeper into the tails which is more sensitive to imperfections in matching standard deviation, not being able to get below 0 hits, etc. \$\endgroup\$ Commented Mar 7, 2023 at 9:10
  • 3
    \$\begingroup\$ @Eddymage: it continues to work fine as long as the hit probability doesn't move too far away from 50% \$\endgroup\$ Commented Mar 7, 2023 at 12:55
  • 2
    \$\begingroup\$ @Eddymage: You can't reliably model the original distribution anyway (see Alan's answer), so at best you will have an approximation. \$\endgroup\$ Commented Mar 7, 2023 at 13:04
  • 2
    \$\begingroup\$ For 20 attacks, assuming an attack bonus of +0 and an AC of 10 (to keep things simple), one would normally expect an average of 10 hits, including a crit. With this method you get 3d6 hits (average of 10.5) including one crit on average. \$\endgroup\$ Commented Mar 7, 2023 at 13:11