Low-value care is defined as the use of a health service, such as diagnostics and treatments, for which the harms or costs outweigh the benefits. In pediatrics, investigations or treatments can be unpleasant or traumatizing to the child, can prolong the time spent in hospital, and can create a cascade of further futile investigations and treatments. Several of the commonly used diagnostics and treatments in bronchiolitis are considered low-value, making it a great model to study low-value care in pediatrics. The purpose of CareBEST is to study the use of 6 low-value healthcare services in children aged 1 to 12 months hospitalized with bronchiolitis, their costs, and measure the variability in practice of these services. The main questions this study aims to answer are: 1. How frequently are 6 low-value care health services used in children hospitalized with bronchiolitis? These 6 low-value care health services are: 1) respiratory virus testing; 2) chest x-rays; 3) continuous pulse oximetry; 4) short-acting beta-agonists; 5) systemic corticosteroids; and 6) antibiotics. * Are there factors that predict the use of these services? * What are the costs of the use of these services? 2. How much variability is there between different patients, different doctors, and between hospitals in the use of these 6 low-value health services ? 3. Are differences in use of low-value health services associated with patient and family characteristics (like race and ethnicity, socioeconomic status, language), and do these contribute to disparities in care? Participants will have their infant's medical chart reviewed during their hospitalization. They will also have 2 short questionnaires to complete, once during their child's admission to the hospital, and one 30 days later to ask about whether their child required any additional medical care. This analysis will provide a better understanding of treatment of bronchiolitis in Canada and help in the development of effective interventions to reduce low-value care.