EVANSTON, IL—A new report published Friday by researchers at Northwestern University revealed that the majority of knocks at the study door occur at the exact moment the finishing touch is being put on a delicate scale model. “We discovered that 90% of all knocks occur precisely when the occupant is using a pair of tweezers to methodically place the final rigging of a tiny mizzenmast,” read the report, noting that whether the study occupant was assembling a HMS Victory 1:48 or a custom replica Empire State Building, the phenomenon usually transpired after hours of prolonged, silent concentration in which a bead of sweat is just beginning to form on their foreheads. “Another 7% of sudden raps on oaken doors come as the final sheen of lacquer is being applied to a model White House’s siding. Our data revealed that probability of unanticipated knocking doubled in cases in which the builder was wearing a smoking jacket. In rare instances, rather than a knock, we observed a buzzer that literally shakes one’s study.” Researchers added that a secondary study would be needed to confirm the precise moment that delicate scale models collapse.