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Using priming questions to reduce entry errors

Key Points

  • Asking people questions linked to a number they are about to enter in to a machine makes it more likely that they will enter it correctly.
  • It can also help them correct mistakes when they do make them.
  • People made far fewer errors after being asked questions about the format of the number, the quantity it refers to, and the context of the number entry task.

We all routinely enter numbers and it can appear to be mundane. In hospitals, numbers have to be entered in machines all the time. Imagine a nurse giving a patient a drug. The prescription gives numbers for the volume and for the rate it should be given to the patient. The nurse memorises the numbers and uses them to set up an infusion pump: a device that delivers the medication. If they make a mistake, the patient may receive an overdose or underdose that makes them seriously ill. There have been many cases like this that ended with patient deaths. A review published in 2009 revealed that in hospitals in England, 1 patient in 10 is affected by potentially serious medical errors, with half dying as a result. Some of these errors are due to wrong number entry.

Psychologists have discovered that they can influence a person's behaviour by exposing them to something about it beforehand. This may be because of the way our brains deal with concepts and ideas. If concept A and concept B are related (such as dog and barking), the exposure to A will activate both A and B in the brain. This makes people more likely to notice B later on. This phenomenon is called Priming. For example, if you are primed with a picture of a dog first, you are very likely to spot the word "barking" in a collection of letters more quickly.

From psychology to hospitals
There are three important factors associated with nurses entering numbers to set up drug delivery devices. We believe they are related in a nurse's brain just like dog and barking are. The first is the format of the numbers - the way it is written. The second is the actual quantity that the number refers to. It could be the volume or the rate of an infusion. And finally, the nurse's task is always associated with the context of patient, drug, dose, route, and time. Inspired by the priming effect, we designed a collection of questions to help people better register one of the three factors (format, quantity, context) before entering a number. We expected the questions to help people be more attentive when entering numbers later on, and as a result improve the expected accuracy. In the experiments these questions helped people make 41% fewer mistakes when entering numbers than without the questions. They also helped people correct 61% more errors after they made them.

As an internationally respected expert in Human Computer Interaction has noted, this research " … has maximum benefits for healthcare practitioners whose errors can potentially cost lives."

Key people
Karen Yunqiu Li, Patrick Oladimeji, Harold Thimbleby

Li, Y., Oladimeji, P., Thimbleby, H., Exploring the Effect of Pre-operational Priming Intervention on Number Entry Errors, to appear in the Proceedings of ACM SIG CHI 2015.