<h2>ABSTRACT</h2>
<p>How do information provision and consumer choices affect market efficiency in a market with misallocation and rationing? We investigate the introduction of a mobile-phone-based outpatient appointment app that provides real-time hospital information and streamlines appointment booking in China's public hospital market. We find the app can significantly improve healthcare access and the matching between patients and providers, achieved through facilitating patient sorting over time and across hospitals based on medical needs. Patients with mild conditions are directed to primary-care providers, while acute-care hospitals are better able to serve patients with severe conditions. We also observe improved patient health outcomes and reduced medical spending. Our findings underscore the power of lightweight healthcare IT innovations in enhancing medical resource utilization and patient welfare.</p>