The emergency department (ED) constitutes a high-risk environment for errors and poor quality of care. Pediatric patients are at increased risk of medical errors. We postulate that implementation of a patient-centered health information technology - ParentLink - can address system-level deficiencies and the unique “just-in-time” information needs of ED physicians and the parents of ill children. The proposed work delivers an innovative product – an electronic interface linked to a pediatric knowledge base that integrates parent-derived data with best practices for safe and effective emergency care across common pediatric disease conditions: otitis media, urinary tract infections, asthma, and head trauma. The study has two aims, the first of which addresses critical gaps in data capture: to evaluate the completeness and accuracy of information on symptoms, disease condition, medications and allergies generated by parents using ParentLink versus information documented by ED physicians and nurses, using structured telephone interviews as a gold standard. The second aim measures the ParentLink’s impact on ED patient safety and quality, specifically: a) the error rate for ordering and prescribing of medications during ED care, and b) the percent of ED visits that adhere to national evidence-based guidelines. Parentlink will be rigorously evaluated in a clinical trial at two diverse ED sites and will use a sequential, non-randomized observational design with two intervention and two control periods to measure the effects of ParentLink on data capture and safety and quality of patient care.