This is a usual care-controlled superiority clinical trial platform designed to evaluate the effects of hospital-based CDS in the ED (CDS-ED) and after transitioning to the hospital setting (CDS-TR) on antibiotic prescribing and related clinical outcomes for child and adolescent LRTI encounters at 3 U.S. children's hospitals. The investigators hypothesize that both interventions will be superior to usual care and, among patients presenting in the ED and subsequently admitted to the hospital, the combined interventions (CDS-ED + CDS-TR) will be most effective overall. Randomization will occur sequentially in two stages corresponding to the ED CDS and Transitions CDS populations. The first stage of randomization will allocate qualifying ED encounters 1:1 to CDS-ED vs. usual care alone in the ED. The second stage of randomization will allocate participants requiring hospitalization (those discharged from the hospital are not eligible) 1:1 to CDS-TR vs. usual care at the time of admission. To minimize bias, the trial will be embedded within clinical care with minimal exclusions and disruption to usual care activities. Investigators will be blinded to study arm assignment, though blinding of treating clinicians is not possible due to the nature of the study. The trial will also evaluate process and implementation outcomes throughout the study period within the platform population. A formal interim analysis is not planned.
