A respiratory physician who I worked for had an uncanny ability of predicting the diagnoses the admitting junior doctor would fail to consider in patients presenting acutely with difficulty in breathing. He was using a checklist, which he developed after years of observing his housestaff.

As a surgical intern I was once praised for my presence of mind in cross matching blood for a patient with a rare blood group who was undergoing a simple nephrectomy. As it turned out she did not need much blood but had she, it would have taken longer than usual to acquire the blood due to the rarity of the blood group.

Presence of mind? Hardly. I was faithfully following a checklist developed by the previous intern which stated, among other things, when in doubt cross match for abdominal surgery. She also warned me of the consequences of failing to do so: I risked being yelled at by the surgeon.

Checklists are everywhere in medicine. Physical examination: That’s a checklist. Clinical history: checklist. Review of systems: checklist. Branches of the abdominal visceral arteries as one searches for an arterial clot in suspected bowel ischemia: checklist. Acute Trauma and Life Support primary survey: checklist.

Checklists enable a systematic approach in clinical medicine. This is particularly important in medical emergencies where the first casualties of panic are knowledge and coordination. As Atul Gawande described in the Checklist Manifesto, systematic recollection of the 4 H’s and 4 T’s identified the cause of and revived a patient from electromechanical dissociation (a form of cardiac arrest).

Checklists facilitate vigilance. It’s important not to confuse the directionality. Vigilance produces checklists. Checklists alone do not produce a culture of vigilance.

Effective checklists are, for the most parts, personal. I have three sets of checklists when interpreting imaging. One for the ICU chest x-rays which contains life-threatening disasters such as misplaced endotracheal tube, one for the poly-trauma patient which contains common areas to look for evidence of organ injury such as the pelvis, and one for the non-emergent patient which contains anatomical regions I have historically most commonly neglected.

It’s unlikely that my checklist will be helpful to others. It’s unlikely that I will find a standardized checklist developed by experts helpful either.

Effective checklists evolve with time. Early on in my residency I tended to forget the appendix unless specifically asked about appendicitis on CT scan of the abdomen. For several consecutive CT scans, I would force myself to recant aloud, “I see (or don’t see) the appendix and it is normal (or inflamed).” That was a checklist of sorts. I look for the appendix automatically now.

So how does one interpret the recent study from Ontario in NEJM which failed to show that government-mandated use of the WHO surgical checklist improved surgical outcomes?

Some have concluded that it shows checklists are useless. That’s, of course, patently absurd considering checklists in medicine are as ubiquitous as cement in a building.

Some caution that the fault lies with the users of the checklist not the checklist itself: It just wasn’t used properly. That’s a distinction without a difference. Checklists should be judged, as drugs are in clinical trials, on intention to use.

Still others have found methodological flaws in the study design. Well, of course, a study will have flaws when its findings don’t support our weltanschauung.

I offer another interpretation. There already was a high degree of vigilance and the surgeons were already using, albeit implicitly, their own checklist developed from years of experience. In such an environment the incremental value of a standardized checklist is likely to be low and forcing its implementation could be counterproductive.

Mandates can effortlessly convert judicious vigilance to slavish compliance. Checklists can become the end rather than means of achieving the end. If I have to specifically document in an imaging report that I have looked at the adrenal glands and they were normal (or abnormal) I might unconsciously worry more about the documentation than the search that the documentation seeks to guarantee.

Alarm fatigue, tuning out, losing the big picture are the intangible harms of dogmatic compliance that studies cannot meaningfully measure. To prove compliance there needs to be visibility or documentation of participation. The aforementioned respiratory physician did not carry a clipboard with the checklist of commonly missed diagnoses. It was buried in his cerebral cortex, but it was no less a checklist for not being visible.

Checklists have emerged organically from the culture of vigilance and safety that have been the bedrock of patient care in clinical medicine. How ironic would it be if we harmed the very culture which gave rise to checklists by mandating its use by a top down decree?

Perhaps we should encourage physicians to develop and use a checklist rather than mandate that they use the checklist. This is the basic difference between vigilance and compliance.

Saurabh Jha is a radiologist and can be reached on Twitter @RogueRad.