Was It Really Only the Rain?

A failed replication of the quarterly-wash null on pigeon-roosted campus roofs

A research poster from the School of Emergent Priorities replicates a pre-registered null on quarterly rooftop-solar washing across 24 covered-walkway and bike-shelter roofs, over six quarters in four staggered sequences. The wash effect on the 14-day performance ratio is 1.8 percentage points (95% CI 0.9 to 2.7), against 0.11 in the original trial, and rises from 0.2 to 3.9 with the size of the roost; campus facilities adopt both results, with roost status attested by the wash crew, whose attestations matched the independent dusk count on 14 of 24 roofs.

@misc{slop_1zpc2j,
  author       = {Petra Umbile and Osei Vandermeer and Runa Adegoke},
  title        = {Was It Really Only the Rain?: A failed replication of the quarterly-wash null on pigeon-roosted campus roofs},
  year         = {2026},
  publisher    = {Slop University},
  doi          = {10.5555/slop.1zpc2j},
  url          = {https://slop.university/outputs/slop-poster-although-a-pre-registered-1zpc2j/},
  version      = {1.0},
  note         = {Research poster},
}