Can risk be managed without measuring it?

Risk managers (and many in other fields) sometimes explain "You cannot manage what you cannot measure". Let's try the umbrella test.

For people who can afford and have access to options, such as umbrellas and real-time weather forecasts, some observed decision categories are:

1. Always carry an umbrella.
2. Never carry an umbrella, but be ready to get wet.
3. Never carry an umbrella and not be ready to get wet.
4. Look outside and then decide whether or not to take an umbrella.
5. Step outside and then decide whether or not to take an umbrella.
6. Look at weather forecasts and then decide whether or not to take an umbrella.
7. Measure parameters including different types of air temperature and humidity, possibly also taking a time series and perhaps plugging them into a model, maybe an ensemble of models. Then decide whether or not to take an umbrella.

Which decision categories do you and those around you adopt? Many people are in categories 1-5, at times disdaining categories 6 and 7. This risk is commonly managed without measuring it.

Academic fields within philosophy, notably epistemology and the history and philosophy of science. theorise and explore  the practices of knowledge and wisdom based on experience , with extensive  disaster risk reduction work drawing on and implementing it. Examples range from  community emergency response teams to  vulnerability and resilience mapping . Decision-making under uncertainty , without necessarily having measurements, is another whole area of study and practice.

Many societies apply traditional, vernacular, Indigenous, and local observations which do not involve measurement in the sense of decision categories 6 and 7. Definitions of "measure" and "manage" require more discussion, especially considering  different cultures of numbers , counting, and quantification.

Under many circumstances, certain measurements cannot be done by human beings without instrumentation or a large degree of technical expertise. Looking back through geological times, far beyond when humans were a species, means that collective or cultural memories would play limited roles, since human memory did not exist. Human abilities have limits for how deep into the Earth and how far into outer space we can observe without technology.

Being able to identify space objects heading for the Earth and being ready to nudge them to miss the Earth is disaster risk reduction. Measurement is essential for managing these risks. Same with knowing where, at some point in the future, a volcanic fissure might crack the Earth’s surface and release fountains of lava.

Many risks require measurement for management. Just not all of them.

The umbrella test neither obviates nor diminishes risk knowledge involving measurement. It simply indicates that not all risks could be revealed by measurements beyond a human being’s capability to observe the environment around them.

Other examples of common risk management without measurement, offering plenty for disaster risk reduction:

1. Latching cupboard doors and securing furniture due to earthquake possibility without looking into earthquake probability.
2. Being vaccinated.
3. Storing woodpiles and other flammable materials away from one’s home in a forest.
4. Seeing icy sidewalks, so putting on cleats or working from home.
5. Heading indoors as soon as hearing thunder .

In summary, "You cannot manage what you cannot measure" as a universal risk rule ought to be reconsidered. The umbrella test demonstrates that we can and do manage risks without measuring them in multiple ways, leading to the corollary "You should manage what you cannot measure".

See also this article and this one.

Ilan Kelman (Instagram/Threads/X @ILANKELMAN and Bluesky ilankelman.bsky.social) is Professor of Disasters and Health at University College London, England and a Professor II at the UiT The Arctic University of Norway. His overall research interest is linking disasters and health, integrating climate change into both. Three main areas are: (i) disaster diplomacy and health diplomacy; (ii) island sustainability focusing on safe and healthy living and livelihoods; and (iii) risk education for health and disasters.