Rounding of birth weights in a Neonatal Intensive Care Unit over 20 years

Objective To determine the frequency of birth weight digit preference for infants admitted to a large neonatal intensive care unit (NICU), the scale of rounding and its dependence on birth weight, and time and the impact on prescribing accuracy. Design A consecutive cohort of birth weights extracted retrospectively from a single clinical database. Setting and participants Birth weights from 9170 inborn infants recorded on an electronic prescribing database admitted to NICU over 20 years. Statistical approach Data are presented for the frequency of each of the possible pairs of final digits. A statistical model of digit preference assuming rounding is used to quantify the proportions rounding to specific accuracy levels. These proportions are compared between those