You don't fatten a pig by weighing it, or do you?

This expression is heard frequently in the world of education and it is a comment on the perils of measurement for measurements sake. The purpose of weighing the pig is to see whether it has put on weight and from that to see what needs to done to help the it gain weight. The act of weighing it alone is generally not regarded as sufficient. Action it is said, must be taken based on the results.

Staff in the NHS spend a lot of time measuring, recording and auditing their clinical activity against a variety of measures such as QOF, QUIPs, CQINS and other targets such as the 4 hour wait, the 2 week cancer and 18 week target. Almost not a month goes by without another edict arriving requiring more measurement to be recorded and reported. This emphasis on the tick box and target culture of the NHS has been criticised by the press and politicians alike although it still abounds. The debate goes on about whether all of this is a help or a hindrance in the care of patients. Comparisons are often drawn with the airline industry and its impressive safety record which relies in no small part to extensive checklists. But is healthcare the same as flying a planeload of passengers across the world?

Recently we introduced the World Health Organisation surgical checklist into our cardiac catheter laboratory. I though it would be useful to re-read the original New England Journal of Medicine article which provides the scientific evidence for the checklist. Initially I was impressed. Taken at face value implementing this simple checklist would reduce our mortality by 40%.  If this were true then it would be remarkable particularly as the intervention is cheap and simple. The study analysed the effects of introducing a surgical safety checklist in 8 hospitals, half in the developed and half in the developing world. Whilst the overall result was impressive, the majority of benefit was seen in hospitals in the developing world where it is likely that patient safety systems were less advanced. Despite this there appeared to be still a small benefit in the hospitals in the developed world which is more difficult to explain since these almost certainly had extensive protocols and surgical checks prior to the implementation of the checklist. One reason to explain why the checklist may have had a beneficial effect is a phenomenon known as the "Hawthorne Effect."

The Hawthorne effect describes how people change their performance in response to being observed.  The original data comes from a study performed at the Western Electric Hawthorne Factory in Cicero, Illinois. This factory employed more than 40,000 workers to make telephones and switchboards. The employees were assigned to precisely measurable tasks on hundreds of assembly lines. In the 1920s a series of behavioural experiments were performed to try and improve productivity. They studied the effects of lighting on worker efficiency and at the start there was no correlation between productivity and light levels.  The workers were then divided into 2 groups for study. Surprisingly just doing this led to a rise in productivity which was equal in both groups. Then they started to progressively reduce the lighting levels until the test group complained they could not see to work. The productivity of both groups again rose in parallel. Next the light bulbs were changed each day in front of the workers and they were told the new bulbs were brighter. The workers commented on the change and increased their productivity even though the new bulbs were no brighter than those that had been removed. These experiments showed that productivity was more related to what the workers believed and not any objective change in their environment. This might be regarded as a workplace demonstration of the placebo effect and may explain why patients who are in the placebo arm of controlled clinical trials usually do better than real world patients. As one cardiologist recently put it: "If I was taken to the emergency room with chest pain the first request I would ask is: Please can I go into a clinical trial?"

The Hawthorne effect demonstrated that people change their behaviour when they think they are being watched and this principle has widespread implications in medicine. Simply instituting a checklist may improve the quality of care because the medical staff know they are being monitored. So perhaps in the end you might fatten a pig by weighing it especially if it knows it is going to be weighed and someone is recording the data.

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The Hawthorne Factory Production Line

A Surgical Safety Checklist to Reduce Morbidity and Mortality in a Global Population.

Harvard Business School and the Hawthorne Experiments (1924-1933)

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