When Dr Gurpreet Dhaliwal, an associate professor at the University of California in San Francisco, comes on stage to make a diagnosis, the audience looks on as if the doctor is performing magic. Considered to be one of the most astute diagnosticians, he 'thinks out loud' as a patient's case history, physical findings, and laboratory tests are presented to him.

The cases presented are usually difficult and most of the time the audience is packed with knowledgeable medical professionals. There are even some who will note with glee if he falters and makes a mistake. But more often than not, Dhaliwal gets the diagnosis right and the crowd erupts in applause.

Doctors follow a similar process during checkups as well. When a patient visits her physician, ideally the doctor should listen carefully without interrupting too often.A physical examination is usually performed and the patient is ordered to undergo tests if necessary. If the doctor can obtain a coherent story, a diagnosis is established.

However, many times there may be a lot of 'noise' (in the history the patient gives, in the physical exam findings, and in the subsequent test results) that can be misleading. These 'noises' (as opposed to the 'signals') can lead doctors astray from proper diagnosis.

The vital question is, can computers outperform doctors like Dhaliwal and make more accurate diagnosis? There is no question that a computer can supplement the thinking of an intelligent clinician. Long after checklists were effectively put in place in training pilots, the medical profession recently caught up and introduced checklists to help with a wide range of activities, from helping make surgery safer to making diagnoses more accurate.

A popular diagnostic checklist program called Isabel is available in the market to ascertain that something has not been overlooked in arriving at a diagnosis. But for routine problems, most doctors will be reluctant to use this program as this will add one more 'thing to do' to their hectic schedule.

So doctors like Dhaliwal will continue to impress us with their knowledge and use it in making accurate diagnosis. But programs like Isabel are here to stay because even when doctors may dismiss a case as 'routine', Isabel will be there to remind them to take another look at the checklist.