number of encounter rounds vs. hit points of monsters

[ggroy]

Anybody worked out formally, the average number of rounds it takes to kill a monster with a certain number of hit points?

The easiest case I can think of which can be worked out, is where one is given the probability P of one player hitting a single monster with H number of "health units". ("Health units" can be hit points, or a fixed (or average) number of hit points of damage done with each hit). The result for the case where one "health unit" of damage is done each time a singler player hits a monster, is

N = H/P, where N = average number of attacks to kill monster

and the variance of N is

var = H (1-P)/(P^2)

(The square root of the variance is what is relevant, which gives a rough idea of what the standard deviation is around N).

[AllisterH]

You would need to add in more factors in the equation.

To begin with, what edition are we talking?

For example, the loadout of the PC (a.k.a magical items) would have a huge effect and previous to 3e, there was no fixed idea as to what the loadout would be.

(seriously, could you even calculate this for pre 3e characters? See the thread right now where we're debating 1e adventure modules - magical equipment could vary widely it seems)

[ggroy]

Originally Posted by AllisterH

You would need to add in more factors in the equation.

Of course.

Originally Posted by AllisterH

To begin with, what edition are we talking?

The simple model is edition independent. Essentially it is a model of one player hitting one monster with H hit points. Each time the player attacks the monster, there is a probability of P of the player hitting the monster and doing 1 hit point of damage.

Originally Posted by AllisterH

For example, the loadout of the PC (a.k.a magical items) would have a huge effect and previous to 3e, there was no fixed idea as to what the loadout would be.

(seriously, could you even calculate this for pre 3e characters? See the thread right now where we're debating 1e adventure modules - magical equipment could vary widely it seems)

If the magical items increase the chance to hit, it would be reflected in the higher probability P of a player hitting a monster.