A new investigation, conducted by Aranzazu Vinas and Helena Matute of the University of Deusto, Bilbao, and Fernando Blanco of the CIMCYC at the University of Granada, highlights the dangers of incorrectly classifying patients. These dangers range from fostering the unfair distribution of healthcare resources to modifying the perceived efficacy of treatments.
We know that both resource scarcity and expectations of efficacy influence people's preferences and decisions in the health domain. But how do these two factors (scarcity and expectations) interact when combined? Why, for example, were specific groups of patients (primarily the elderly and those with disabilities) so clearly discriminated against during the COVID-19 pandemic, when medical resources were particularly scarce?
To answer this question and understand medical decisions in situations of scarcity, two experiments were conducted in which participants had to imagine they were medical professionals. They were then shown a series of fictitious patients and had to decide whether or not to administer treatment. Immediately afterward, they were informed of the outcome. The key element of this research is that the patients were labeled as either highly sensitive or not very sensitive to the treatment, which induced certain efficacy expectations (high or low) for that treatment. Furthermore, half of the participants were assigned a scarce budget to “buy” doses of the treatment, and the other half was assigned an abundant budget.
In reality, the patient labeling was incorrect, and all patients recovered with the same probability—meaning they were equally sensitive. In the first experiment, the treatment was effective (administering it increased the probability of recovery), and in the second experiment, it was totally ineffective (it did not increase the probability of recovery).
The results showed that participants tended to reserve the treatment for patients labeled as sensitive, especially when resources were scarce. This resulted in the incorrect judgment that the treatment was more effective for these patients. This occurred even in the second experiment, where the treatment was completely ineffective in curing the patients, yet many participants believed that it worked.
Ultimately, the incorrect labeling of patients caused participants to distribute their resources (in this case, treatment doses) unfairly, and it also interfered with their ability to learn from the available evidence.
Thus, it can be concluded that resource scarcity, combined with prior expectations (in this case induced by an erroneous classification system), can result in the inappropriate use of resources and, more worryingly, hinders the ability to learn from evidence and correct one's own errors.
Reference
Vinas, A., Blanco, F., & Matute, H. (2025). The combined effect of patient classification and the availability of resources can lead to biased perception of treatment effectiveness. Scientific Reports, 15, 15915. https://doi.org/10.1038/s41598-025-01043-w
Contact at the CIMCYC
Fernando Blanco (@email)