I've given two open-book tests back-to-back, but grades aren't any better than if the book were closed. My 6th graders are too lazy to actually go back and reread a stanza of a poem to determine who said what to whom (Walrus & The Carpenter). Since my test grades tend to be ultra-low, this is a major reason tests don't count any more than daily assignments. I tell kids that if tests are hard to pass, they need to do the other assignments that aren't as challenging. the reason my kids fail my class or eak by with a 70 is because a) they are absent a good bit; b) they don't finish work, think they'll do it for homework, and then don't turn in late work; c) they just don't do the assignments and therefore have nothing to turn anyway; or d) they just put anything down on the paper to get 'er done without regard to actually thinking first.