In a previous post (Initial Thoughts on LotFP Playtest Document 0.1 Part 2 of 2), I discussed the new saving throw system in the Playtest Document that was recently distributed to Pembrooktonshire Gardening Society members who purchased print products from the LotFP webstore. The new rules in this document are tentative, of course, but it's possible that we'll be seeing this saving throw system or a similar one in the next official edition of the game (not counting reprints of the current Rules & Magic book, of course - the new edition is still a long way off, according to James Raggi).
In the aforementioned post, I mentioned some places online where you can find some of the math related to these new saving throws. However, I couldn't seem to find a complete breakdown of all of the probabilities of success. I wanted to figure it all out myself, but unfortunately, I suck at math.
Thankfully, a mathematically inclined friend recently visited me, so I asked him about it. He found the relevant formula online HERE. Working from that, I did some algebra on a literal napkin, and these are the probabilities that I came up with. It is very possible that I made some mistakes, and I also admit to being quick to round many of the numbers involved, so please tell me if you see some way in which I screwed up here. I apologize for any errors.
Probabilities of Successful Saves - Playtest Document 0.1
2d6 = About a 30.6% chance of at least a partial saving throw, about a 2.9% chance of a full saving throw.
3d6 = About a 42.1% chance of at least a partial saving throw, about a 7.4% chance of a full saving throw.
4d6 = About a 51.8% chance of at least a partial saving throw, about a 13.2% chance of a full saving throw.
5d6 = About a 59.8% chance of at least a partial saving throw, about a 19.6% chance of a full saving throw.
6d6 = About a 66.5% chance of at least a partial saving throw, about a 26.3% chance of a full saving throw.
For comparison, a first level Fighter with average ability scores in the current edition of the rules has a 35% chance of success vs. paralysis, a 45% chance vs. poison, a 30% chance vs. breath weapons, a 40% chance vs. devices, and a 25% chance vs. magic.
Again, I apologize if my math is wrong. Please feel free to correct me. Also please remember that I rounded a lot of numbers in my calculations.
Make what you will of this data. I'm not entirely sure how I feel about this change. I've heard people express the opinion that this system is too harsh. If all you care about is getting at least a partial saving throw, I think these numbers are fairly generous, considering that the average saving throw (based on average ability scores) would be 4d6 - it's greater than what a first level PC would usually get in the current rules.* But if you're talking about making a complete success, the chances are incredibly reduced in the Playtest Document. Considering that partial successes don't exist in the current version of Rules & Magic, this latter comparison may be more apt. If so, I honestly can't say I'm pleased with this change. Dropping from an average of 25-45% to 13.2% seems a bit severe. I could see this game getting pretty discouraging for players pretty quickly if they're already happy with the way things are done in other D&D/OSR games, or if they're just newcomers who haven't gotten on board with keeping half a dozen backup characters on hand at all times. I'd love to hear what other people think of this whole idea. I bet James Raggi would, too, considering that this comes from a Playtest Document.
*Not nearly as great as what high-level characters can get in the current rules, but my understanding is that most LotFP groups never make it to high levels, and besides, one could argue that the saving throws for such characters are too generous in the current edition. Just ask my wife, who currently plays a level 20-something Dwarf who practically doesn't bat an eye at saving throws.