The urinal dispersal function, sometimes symbolised as ‘ρ’, is the mathematical function that describes to an arbitrary degree of accuracy the sequence in which men choose the urinal at which to relieve themselves in public conveniences. Values of ρ vary in accordance with the following variables:

- Number of urinals (
*n*)
- Number of other urinal users (
*i*)
- Degree of shyness (
*s*)
- Urgency of visit (
*u*)

In normal situations (i.e. those in which *s* is approximately 0.5 and *u* tends towards zero), a familiar pattern emerges in which the first attendee occupies the furthermost urinal, the second the one at the opposite end, the third at an equal distance between the first two, and so on until each position is occupied. Further complexities are introduced when *u* is increased, thereby favouring selection of the closest urinal to the door, and with different values of *s*, such as with friends who arrive simultaneously (a relatively rare occurrence) and occupy adjacent urinals. Conversely, where *s* exceeds 1.0, users may choose to forego the urinals entirely and relieve themselves in the comparative privacy of a toilet cubicle.