Risk preference and laboratory test selection.

The risk preferences in situations of potential gain, and of potential loss, expressed by 67 physicians were correlated with the numbers of laboratory tests they selected after review of identical copies of two outpatient charts. Physicians who chose a 50/50 gamble of losing ten or no years of life expectancy over an equivalent certain loss of five years selected twice as many tests as those who chose the loss (p less than 0.025). Risk preferences may provide some insight into why some physicians order more laboratory tests than do others.