Population phi
0.000
Berkson's Paradox Simulator
Filter independent traits on a shared selection rule and see the selected-sample association emerge.
Selected phi
-0.500
- Selection rule
- selected if A or B
- Selection rate
- 75.0%
- Mean simulated selected phi
- Not run
| Cell | Population | Selected |
|---|
Run the simulation to fill Monte Carlo metrics and convergence.
| Trial | Mean selected phi |
|---|
phi = (both * neither - A-only * B-only) / sqrt(row and column margins)
How?
How this is calculated
The full population starts with independent binary traits. The selected sample keeps only cases where trait A or trait B is present, which removes the neither cell and can create a negative association.
Formula: phi = (both * neither - A-only * B-only) / sqrt(row and column margins)
Sources
- Berkson's paradox overview. Wikipedia. Retrieved .
- Collider effect educational note. arXiv. Retrieved .
Method last reviewed