There have been many times when I’ve had to adjudicate ‘luck’ during game sessions. Sometimes, it’s as simple as determining whether something would be readily available (“hey, we’re in a tool shed! Is the power drill charged?”) or fortuitously brought along (“I know I didn’t mention it, but my character probably would carry chewing gum in her pocket”). Usually on these occasions I just use GM fiat or make up a percentage chance; still, it would be handy to have something meatier.
While playing The Laundry (which is a variant ofÂ Call of Cthulhu) a few nights ago, I was pleasantly surprised at how convenient it was to have a Luck score available for me to use. Whenever I needed fortune to fall in a PC’s favor I simply had her make a Luck roll. This came in extremely handy when one PC, left behind as the other PCs took off in a van, looked around to see if there was something he could take. After a successful Luck roll I told him he saw a man just hopping on his scooter.
In Basic Roleplaying (from which the previously mentioned games are derived), Luck is determined by Power, which is a combination of willpower, magical ability, and spiritual awareness. Luck = Power x5, which turns it into a percentage. If you roll under the percentage, then luck is on your side. Easy rolls double the percentage, Difficult rolls halve it. Special rolls are at 1/5th the success percentage (indicating either a spectacular success or what is needed for a very difficult roll), while Fumbles are at 1/5th the failure percentage; your bad luck just got worse.
So while running The Laundry, all I needed to do was decide whether luck was really on the PC’s side (Easy), about 50/50 (Normal), not that likely (Difficult), or really a stretch (Special). If the PC made the roll then fortune is on her side. Sometimes I called for the Luck roll based on the situation; sometimes the player prompted me, usually indirectly.
The concept of a Luck stat is easily transportable to other systems although not every RPG has a stat to represent the mystical. Some RPGs, like HERO, GURPS, and Unisystem, have powers or traits (or even some version of ‘bennie points’) that represent luck . Other RPGs, like Dungeons & Dragons in its multiple iterations, don’t have a statistic that easily models Basic Roleplaying’s Power stat. In the case of the former, you’ll need to decide whether a more general Luck stat is necessary, and in the latter you’ll need to decide how to derive a luck score.
For example, adding Luck to a d20 game is simple; take the average of all a PC’s ability scores in order to find the Luck stat (for the Elite array it’s 12, or +1). Then, decide whether your PCs lead charmed lives or whether the weaker PCs get the lucky breaks; flip the modifier if you go with the latter (so a +1 becomes a -1). Grant the PC 4 “skill ranks” in Luck and add 1 for each level above 1st. Now you can treat luck like any other skill and use difficulty levels to simulate the likelihood of luck being on the PC’s side. One can never “take 10 0r 20” on Luck rolls. A ‘Lucky’ feat could add a bonus.
Alternately, you could simply run Luck as straight percentages for any system, so long as you have appropriate dice handy. Easy rolls are 75%, Average rolls are 50%, Difficult rolls are 25% and Special rolls are 5% (in addition to numerous values in between).
So, what kinds of things can Luck be used for?
1. Serendipity: Obstacles are bypassed because something happens to aid you (the villain closes the elevator door but the doors to the adjacent elevator aids you. The person you’ve been looking for just happens to stop at the same fast food joint for lunch.
2. Props: You’re out of bullets and trapped in a shed when the monster attacks. How lucky would it be if this backwoods shed had an extra shotgun in it for emergencies?
3. Relationships: How are you going to get into that exclusive club? Hey wait, didn’t that bouncer go to high school with you? And didn’t you happen to help him out of a jam in the past?
4. Trivia: No, you aren’t a historian, but you just happen to enjoy the Elizabethan era; so much so that you’d be familiar with the works of John Dee. This just happens to be extremely useful in interpreting the ritual you just stumbled into.
5. Skill: While you didn’t take any ranged combat skills, you may recall that you did a bit of archery during a couple of summer camps. Maybe that’s enough for you to perform a trick now?
The downside to adding Luck, of course, is that you’ve created another statistic to track or, in some RPGs, risk watering down or usurping a mechanic already in place. Still, I’ve found that having some luck mechanic in place helps mitigate concerns of GM fiat, railroading, or convenience.
How about you? How do you incorporate the role of Luck in RPGs that lack a mechanic for it? Do you stick with GM fiat or do something else? Do you think adding a Luck mechanic would help your campaign or just complicate it?