Scheduling Pre-Operative Assessment Clinic via Answer Set Programming Simone Caruso 1 , Giuseppe Galatà 2 , Marco Maratea 1 , Marco Mochi 1,2 and Ivan Porro 2 1 DIBRIS, University of Genova, Genova, Italy 2 SurgiQ srl, Italy Abstract The problem of scheduling Pre-Operative Assessment Clinic (PAC) consists of assigning patients to a day for the exams needed before a surgical procedure, taking into account patients with different priority levels, due dates, and operators availability. Realizing a satisfying schedule is of upmost importance for a clinic, since delay in PAC can cause delay in the subsequent phases, causing a decrease in patients’ satisfaction. In this paper, we divide the problem in two sub-problems, and present the results of a first preliminary analysis of the two problems based on Answer Set Programming (ASP). In the first sub-problem patients are assigned to a day taking into account a default list of exams; then, the second sub-problem, having the actual list of exams needed by each patient, use the result of the first sub-problem to assign a starting time to each exam. Keywords Healthcare, Pre-Operative Assessment Clinic Scheduling, Answer Set Programming 1. Introduction The Pre-Operative Assessment Clinic (PAC) scheduling problem is the task of assigning patients to a day, in which the patient will be examined and prepared to a surgical operation, taking in account patients with different priority levels, due dates, and operators availability. The PAC consists of several exams needed by patients to ensure they are well prepared for their operation. This allows patients to stay at home until the morning of the surgery, instead of being admitted to the hospital one or two days before the scheduled operation, moreover, reducing waiting time between the exams increase patient satisfaction [1] and avoid the cancellation of the surgery [2]. The problem is divided into two sub-problems [3]: in the first sub-problem, patients are assigned to a day taking into account a default list of exams, and the solution has to schedule patients before their due date and prioritizing the assignments to patients with higher priority. In the second sub-problem, the scheduler assigns a starting time to each exam needed by patients, considering the available operators and the duration of the exams. A proper solution to the PAC scheduling problem is vital to improve the degree of patients’ satisfaction and to reduce surgical complications. Complex combinatorial problems, possibly involving optimizations, IPS-2021: 9th Italian Workshop on Planning and Scheduling  4493864@studenti.unige.it (S. Caruso); giuseppe.galatà@surgiq.com (G. Galatà); marco.maratea@unige.it (M. Maratea); marco.mochi@unige.it (M. Mochi); ivan.porro@surgiq.com (I. Porro) © 2021 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0). CEUR Workshop Proceedings http://ceur-ws.org ISSN 1613-0073 CEUR Workshop Proceedings (CEUR-WS.org)