Hi I'm still experimenting with grade and sd statements.. I can get some very extreme distortions with just a small relative difference in sd values. No problem, it's just a function of my mis-close, and the math. To my advantage it may help me to decipher the scope/visibility of grade statements if I can concentrate on the problem long enough. I finally took the hint in previous postings that BCRA grades 3 & 5 might be built into Therion. I tested it and indeed they are. Is this documented anywhere? Would have saved me quite a bit of experimentation (and embarrassment). I'm still looking for a 'best practice' on where to put grade statements and how to control their scope/visibility. Perhaps someone could write a brief note for the Wiki or the Therion Book? Bruce