When I am assessing the amount of information that students have ended up with in a class (based on all of the learning methods utilized and all experiences in and out of class) and based on the learning literacy of the assessment I can find nice gaussian bell curves. Some students will be bulls eyes with accuracy and reliability. Some students will be reliably wrong. Some will hit all over the target. If students who are otherwise reliable and accurate get something wrong I look to see if it was graded wrong or I taught it wrong. That is how I use accuracy and reliability.

Unfortunately the bell curve has limited utility in much of my research. I deal with binary data that the outliers are the important element. Averages have little in relationship to the rest of the environment. Myself I don't believe very much in trend analysis or other predictive methods. Only that which can be observed. Sure we all do it and it is fun, but prediction even with high reliability is rarely scientific.