Simple heuristics of the type introduced by Gigerenzer, Todd, and The ABC Research Group (1999) embody principles for information search, stop and decision making. These heuristics suggest that such processes are simple. In an analysis of general practitioners' (GPs) information search and decision-making behaviour when prescribing a lipid lowering drug, we examined whether information search was simple, and whether a heuristic that predicts a simple decision-making process was also accurate at describing information search. We found that GPs' information search behaviour was simple in that it demonstrated characteristics of the matching heuristic (e.g. stopping rule). In addition, although the matching heuristic which correctly predicted on average 75% of GPs' decisions used significantly fewer cues on average than the GPs did in the information search task, it was reasonably accurate in describing order of information search. These findings have implications for the validity of simple heuristics describing both information search and decision making. Copyright © 2009 John Wiley & Sons, Ltd.