Why is it that my third spell, unless it is a 100% spell, has only a 70% success rate? I can cast two wand spells in a row (100% success rate), and when my third spell percentage is 85% it only works 7 out of ten times? This happens consistently. I've played several different characters and it has happened with every one. If I cast 3 100% spells in a row the fourth is only effective 75-80% of the time unless it is also 100% effective.
What's your sample size there? Humans are notorious for having terrible intuition about probability. That's why, for example, so many people play the lottery.
If you only counted ten times, even if the true chance of each spell hitting is 85%, the probability that at most seven of the ten hit is about 18%. That's easily explained by random chance.
In order to credibly assert that the spell percentages really are off, you'd need a much larger sample size. Start writing down what happens in your battles, and keep track of the results of every single attempted spell that you use that should theoretially have an 85% chance. Do this for hundreds of spells, and see if you come close to 85% hitting.
Be warned that a lot of people who try this will track the data wrong. If you only count most of the time, but don't pick up all of them, your natural bias will probably be to always include fizzles, but sometimes forget to include attacks that hit. That will make your results complete garbage.
Conversely, it's vital to exclude anything that doesn't have a theoretical 85% chance of hitting (which I assume is your main class spells, as a death or balance wizard). That means excluding not just wands and secondary spells, but also any spells where you have accuracy buffs or debuffs. Mix in spells with the wrong probability and the percentage that hit theoretically shouldn't converge to 85%.
The only probabilities that intuitively strike me as being off are ice spells and necklace spells being too low, and power pips being too high. None feel far enough off for me to suspect that they really are wrong.
I have been playing for several weeks now and though I realize that this is not a LONG time, the game is quite repetitive. My level 24 Adept Necromancer is my highest toon of six. I play my basic spell deck when I use him, so my 1,2,3 is always wand,wand,ghoul. At lvl24 I have cast this spell 326 times. Yes I kept count. It is my second toon and I started it after I noticed inconsistencies in my first toon. The percentage rate is actually 72% as it has fizzled 91 times.
I contend that the success rate is situational to make the game "more challenging" (read: take longer). If they want to make it inconsistant and more boring this is the way to go about it.
To further the situational argument, I have been playing my Balance Wizard more lately and have equipped myself so that I can cast a Sandstorm spell with 99% efficiency. (85% spell+10% spell+ 4%gear). This spell has failed 3 times in less than 50 casts even though it should only fail once in 100! How about it KingIsle? Am I on the "Bad Guy" list for pointing this stuff out? Can I get my luck points increased to match my ingame stats?
the thing your missing is your treating the entire record as a single percentage , 99% chance to hit each time it tries, not to say this is going to make a huge difference , but you can hit a 1% chance two times in a row
This is the point of percentages. 85% means that 85 times out of 100 the spell will succeed. If I have gear and spells that increase my spell percentage to 99% every time I cast a particular spell, I shouldn't expect a spell to fail 4 times in 20 (80%). But that is what has happened. This makes the spell percentages deceptive if not downright WRONG.