Thoughts on "Safety Signalling" in Hospitals

Imagine if people only stopped at red traffic lights sometimes. At any moment, a transversing car could slam into your side! In such a scenario, what would then be the point of having traffic lights? This is actually the situation in many hospitals. It seems strange when applied to traffic, but hospitals are desperately trying to use signal lights, red colours, signage etc. to indicate special safety zones for medicine administration. The problem is that these safety signals doesn’t seem to work. They do not lead to fewer errors and more safety. Like the above fake traffic lights, they are mostly for show.

I have developed the concept of "safety signalling" to describe this phenomenon in hospitals. The conept is reminiscent of the concept "security theater" describing the spectacle of security measures in airports that provide a feeling of security, but doing little or nothing to achieve it. My concept of "safety signalling" is different though because it denotes a situation where the signal is directed internally to the hospital organisation itself - the hospital assures itself of its own safety by putting up posters and red tape. This is different than the security theater where the primary audience is the external world of passengers.

Where Did "Safety Signalling" Originate?

For a year, I have been doing ethnographic field work in danish hospitals. A surprising “discovery” for me was that all medicine rooms, and sometimes entire wards, are considered ‘No-interruption Zones’ (NIZ's). Many times, there will be a sign on the door to medicine rooms or wards, and sometimes red tape on the floor will mark certain areas off for silence. The zones are supposed to counter human medicine error that happen a lot when nurses prepare medicine. What was surprising though, was that I did not notice any difference in communication or noise levels in these zones compared to other places in the ward: people talked, worked together and had private conversations, also when preparing medicine. This was puzzling to me. I decided to look into the evidence behind the NIZ. Scientifically, I could not find any research that suggested that these zones led to fewer medicine errors, although a lot of research on the matter existed. Some studies even suggested that the NIZ produced more interruptions, paradoxically (perhabs because the NIZ allows for a closed, intimate space for collegial conversatio). Across all these studies, one thing was common: most mentioned that the NIZ should "signal" something.

The Interpretation Problem

Clinical studies that experiment with NIZ's need to overcome the problem of communicating to nurses and doctors that they should not interrupt each other. This is the problem of signalling and interpretation. Studies report that the red tape and signs “served as a visible signal that a nurse was administering medications and should not be interrupted” [1] and that “‘do not interrupt’ tabards, sashes or flags (…) signal that nurses are involved in a medication task and should not be interrupted” [2]. What I notice about these studies is their overconfidence in how to interpret the signal. They are sure that the signal is interpreted in the intended way. The question that none of these studie answer is how they expect people to interpret this meaning from the signs and wests - they never adresss the actual interpretations that people read from the NIZ. For example, one sign I encountered said “No-Interruption ZONE” (I have no idea why ZONE was capitalized on the sign). When I asked a nurse why he still talked and interrupted colleagues in the no-interruption zone, he answered that he considered it a zone free from only patient-interruptions, and that staff interruptions were okay. To me, this is a clue of the overlooked attribute of the NIZ, that its interpretation is left to staff themselves. The zone can therefore become anything that staff wants it to be. My hypothesis is that the NIZ is actually primarily "signalling" safety rather than actually providing safety.

Is "Safety Signalling" a Good Concept?

I had the idea of applying the concept of signalling to safety studies because I was reading the (unrelated) book called ‘The Case Against Education’ while going through my ethnogprahy notes. This book presents the idea that most education is almost purely merit signalling and almost no skills learning. The concept of signalling thus stems from economic studies of the value of university degrees. Although it was a radical idea, the “signalling” concept was intriguing to me, and I started to think is the same could be the case with safety in hospitals. What I like about the concept is that is predicts really well the hospital staff's behaviour in the NIZ. I also like that the concept can be percieved as both good and bad - signalling safety is important, but the signal is not enough if it doesn't change behaviour. The psychological feeling of safety is important [3], but it should not replace actual safety. It is my hope that the concept of "safety signalling" can spark reflection in hospitals and hospital research about medicine rooms as spaces of information, rather than purely spaces of medicine.


Image credit: USAISR Burn Center

[1] Westbrook, J. I., Li, L., Hooper, T. D., Raban, M. Z., Middleton, S., & Lehnbom, E. C. (2017). Effectiveness of a 'Do not interrupt' bundled intervention to reduce interruptions during medication administration: a cluster randomised controlled feasibility study. BMJ Qual Saf, 26(9), p. 735.

[2] Westbrook, J. I., Raban, M. Z., & Walter, S. R. (2019). Interruptions and Multitasking in Clinical Work: A Summary of the Evidence. In K. Zheng, J. Westbrook, T. G. Kannampallil, & V. L. Patel (Eds.), Cognitive informatics: reengineering clinical workflow for safer and more efficient care, Springer, p. 109.

[3] Schneier, Bruce (2008). The Psychology of Security (Part 1). Schneier on Security:, accessed march 8th 2021.

Malte Lebahn-Hadidi

Malte Lebahn-Hadidi