Applying Computer Simulation Modelling to Minimizing Appointment Lead-Time in Elderly Outpatient Clinics: A Case Study Miguel Ortíz-Barrios 1( ✉ ) , Pedro López-Meza 2 , and Genett Jimenez-Delgado 2 1 Department of Industrial Management, Agroindustry and Operations, Universidad de la Costa CUC, Barranquilla, Colombia mortiz1@cuc.edu.co 2 Department of Industrial Processes Engineering, Institución Universitaria ITSA, Soledad, Colombia {plopezmeza,gjimenez}@itsa.edu.co Abstract. Appointment lead-time is a pivotal parameter in elderly outpatient clinics. In this regard, delayed medical care may represent complications in the elderly population and the development of more severe diseases. However, healthcare managers are not skilled in methods effectively reducing waiting times. Therefore, this paper presents the computer simulation modelling to tackle this problem. In this regard, the real-world system was initially simulated and then, three improvement scenarios were designed and validated operationally and financially. The results evidenced that Scenario 2 was the best choice since it provided a low investment per reduced day and a significant reduction (47.1%) regarding the probability of waiting for more than 8 days per appointment. With this proposal, the quality of medical care in elderly population can be meaning‐ fully increased and decision-making process can be effectively supported. Keywords: Discrete event simulation (DES) · Outpatient clinics · Appointment lead-time · Healthcare · Elderly 1 Introduction The constant growth in the population increases the demand for better planning and management of the healthcare services. This implies providing medical care with high- quality standards which are relevant when preventing more complex diseases and symp‐ toms [1]. Nevertheless, the hospital managers usually apply conventional methods not considering the interactions between departments in terms of clinic capacity, patient demand, clinical policies and patient behavior. Additionally, they face increasing pres‐ sure to control costs while delivering effective medical care [2]. Therefore, it is necessary to assist healthcare professionals in tackling this particular problem satisfactorily. In this regard, one of the services most affected by interactions between departments is outpatient clinics. Herein, the pivotal process parameter is appointment lead-time. In this regard, long appointment delays are found to cause clinical ramifications, increase patient no-shows [3] and patient dissatisfaction [4]. This evidences that the degree to © Springer International Publishing AG 2017 S.F. Ochoa et al. (Eds.): UCAmI 2017, LNCS 10586, pp. 323–329, 2017. DOI: 10.1007/978-3-319-67585-5_34