Optimizing screening and evaluation process is essential in maximizing recruiting potential participants into clinical trials. We developed a clinical recruiting system used in the management of human research studies whereby recruiting for various protocols are conducted at multiple sites by different groups with process interdependencies. The system is developed based on a multi-tier architecture with a series of real-time and on-demand decision support systems to increase the efficiency of screening and evaluation of participants during a recruiting process. It simulates various conditions by using derivation rules and recruiting templates for automatic generation of checklists in order to recommend the optimum selection rules based on existing participants? data and is seamlessly integrated into our large Human Research Information System, a comprehensive electronic health record (EHR) system for research participants.