This is a technical article for the DC Heroes RPG.
DC Heroes uses tables, and some folks do not like tables. Playing it without tables is thus a subject that has surfaced from time to time on the DCH discussion list.
However, if people have fully run games that way they have not transmitted us their hidden secrets – but we can still make some useful observations for those who would like to experiment.
A rough formula for the Action Table is as follows:
Target Number = AV – OV + 11
This incorporates the optional rule for comparisons of AV/OVs within the same column, but becomes increasingly inaccurate as the AP number get more distant from one another – or higher in general. This is mostly because the columns cover a larger range at higher AP levels.
For example, the Action Chart makes no difference in target number for an AV of 36 versus an AV of 40, but using the formula above it would be a difference of 5.
This widening of Columns seems based on the observation that at high power levels, power differences appear to become less significant in super-hero comic books. If applying the formula above you lose this normalisation, and having a 1 or 2 APs advantage is important no matter what the scale.
As for the Result Chart formula:
RAPs = EV – RV + (2D10 – Target Number + (EV/6(round down)))
It might be easier to drop the EV/6 part, but it is present in the table as published.
Column Shifts are difficult to account for in this system, but can generally be treated as shifting by 2 APs. This makes Column Shifts less impressive at higher AP levels – as previously noted, Columns in the existing tables get wider as the power level increases.
One variation of the Action Table is used in the Underground RPG, which employs a variant of the MEGS system. Roll AV + 2D10 and then subtract OV + 2D10. Both the AV-side roll and the OV-side roll behave like DC Heroes rolls, rerolling and adding on a double.
If the OV roll is equal to or higher than the AV roll, the action fails. If the AV value is higher, then it gives a grade of successes from C to A based on the difference.
As far as I can tell, the biggest differences in this approach would be that the chance of success is slightly lower as the 2D10 w/ doubles roll for the OV would raise the base target number from 11 to (IIRC) 12.1 and the tails of the probability curve are longer due to a wider possible range of results.
See our probabilities in DCH article for more about DC Heroes distributions.
The Underground approach could be applied to MEGS easily enough:
AV+2D10 – OV+2D10= Action Total (AT)
If AT is positive, RAPs equal EV+AT-RV
Tighter and broader distributions
One possible variation for tableless approaches would be to change the dice rolled and adjust the target number to match.
For example, a more realistic Genre might use 2D6s versus a Target Number equal to AV – OV + 7 with only double 6s being rerolled and added. This leads to a lower range of results and a much smaller likelihood of epic results from doubles.
A big action Genre like the early issues of The Authority might have 2D12 versus a TN of AV – OV + 13.
Helper(s): Sébastien Andrivet.
Writeup revised on the 18th of February, 2013.