The misapplication of professional opinion

ing with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or fee. Request permission to publish from: Publications Dept., ACM, Inc., Fax +1-212-869-0481 or email permissions@acm.org For other copying of articles that carry a code at the bottom of the first or last page or screen display, copying is permitted provided that the per-copy fee indicated in the code is paid through the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, +1-978-750-8400, +1-978-750-4470 (fax). m c a : / 6 i n t e r a c t i o n s / n o v e m b e r + d e c e m b e r 2 0 0 5 Here are two particularly dangerous heuristics: