The artificial environment of the psychological laboratory experiment offers an excellent method for testing whether a causal relationship exists — but it is mostly useless for predicting the size and power of such effects out in the world. A laboratory effect may be artificially inflated or deflated in comparison with the same causal process outside the laboratory. Indeed, in many cases the very notion of a true effect size (regardless of type of manipulation or dependent variable) is absurd. At best, effect sizes from laboratory experiments provide information that could help other researchers to design their experiments — but that means effect sizes are shop talk, not information about reality. NOTE: Comment articles are invited at the journal.