2d6 Odds

As far as I can figure 'em, here's the odds for 2d6 leadership rolls:

Ld .. % success
2 ... 2.8
3 ... 8.3
4 ... 16.7
5 ... 27.8
6 ... 41.7
7 ... 58.3
8 ... 72.2
9 ... 83.3
10 ... 91.7
11 ... 97.2

10 is the highest base leadership value that I know of, and I don't think you can ever go above 10 with modifiers. Obviously there are plenty of negative modifiers. One interesting thing to note is that losing a point of leadership at either extreme (high or low Ld) does not produce as devastating an effect as losing a point when your Ld is around 7 or 8. Like Blaine says, you lose it there and you're in a world of hurt. From 8 to 6 is pretty much worst case scenario.

Obviously some armies never have to worry about this at all. Chaos has the most fearless units, excepting maybe Tyranids when placed within synapse distance. Necrons is probably the next best, with all units either fearless or at Ld 10. After that come Marines, whose 'know no fear' gives them most of the benefits of fearlessness without making them take saves for being outnumbered when they lose an assault. Eldar and Orks are middle ground, with Guard and Tau being the most vulnerable.

My original purpose for calculating these odds was to evaluate the benefit of the various ways to beef Ld for my Guard army. In the end I settled with the Iron Discipline doctrine for all my officers, and a Company Banner in the main HQ (see previous post). It takes care of the -1 for being below 50%, allows for a Ld reroll which virtually guarantees success, and to top it off my squads can regroup when below 50%. All this for 5 points per officer (15 total for my army) plus 11 for the standard bearer. Compare that to upgrading officers just for one flimsy extra point of Ld (because honestly the extra attack and wound are useless) and it's a no-brainer. Still, if you do go that route, it's cheaper to give a Junior Officer the Honorifica rather than upgrade him to a Heroic Senior. I love my Commissar model but after I made my Command HQ static with a heavy weapon, his benefit is just not worth the points (40+).