I make no claims about false negative results. But I know that people that I've recommended hiring have basic analytical skills, can correctly code a Boolean predicate with a few connectives in it, and aren't confused by linked data structures. It's not a high bar that I set, and that's kind of my point: ask at least some low-bar questions! You can debate all day about how well candidates have done with the hard questions, but it's pretty easy to know what to do with those who can't cope with something like "do two (x,y,width,height) rectangles intersect or not?".