Rarity Roulette – an interactive simulator for mass screenings

An interactive simulator for visualizing how false positives explode in mass screenings for low-prevalence problems. Relevant across diverse domains including security (e.g., Chat Control; iBorderCtrl), medicine (e.g., mammography; PSA testing), and so much more.

The purpose is to begin to more easily visualize how prevalence, sensitivity, specificity, investigative capacity, and strategic behavior interact to shape real-world outcomes.

Interactive tool: https://verawilde.github.io/rarity-roulette/

Would love feedback, critiques, and ideas for improvements.

I'm especially interested in feedback on the modeling choices — prevalence curves, specificity sliders, and whether (and how) to add correlated errors or adversarial behavior.

If anyone works in health tech, security, or trust & safety, I'd also love to hear how this maps to your practical experience with low-prevalence detection.

If you test the simulator, I'd love to hear what surprised you most — especially if something behaved differently than you expected. Thanks in advance!