# Looking for the crystal ball in unscheduled care: a systematic literature review of the forecasting process

## TL;DR

This paper reviews forecasting methods in unscheduled healthcare services like emergency departments, offering a framework and identifying research gaps.

## Contribution

The paper introduces a novel framework for characterizing forecasting processes in unscheduled care and conducts a systematic literature review.

## Key findings

- A taxonomy is proposed to categorize forecasting processes in unplanned healthcare services.
- The literature review identifies key gaps in forecasting methodologies and reproducibility in unscheduled care.
- The paper highlights the importance of forecasting accuracy for decision-making in emergency healthcare settings.

## Abstract

The ability to accurately forecast unscheduled care needs is of paramount importance for decision making in healthcare operations, ensuring a continuous and high-quality level of care. In this work, we provide a literature review of 156 research articles of forecasting applications with special focus on care services that are not scheduled in advance such as emergency departments. Our paper presents two key contributions. Firstly, we propose a novel framework designed to characterize the application of forecasting process across various unplanned healthcare services. Our taxonomy facilitates the detection, decomposition, and categorization of forecasting processes, enhancing the understanding of their deployment in different unscheduled care settings. Secondly, we conduct a comprehensive literature review based on a systematic search, critically analyzing the state of forecasting research in unscheduled care services and identifying key research gaps. We explore forecasting problems in depth, examining their purpose, the various methodologies used, the rigor used in generating and evaluating forecasts, and the reproducibility of results, all within the context of the proposed framework. By consolidating the current state of the art, this paper provides valuable insights to both healthcare professionals and academics regarding the effective application of forecasting in unscheduled care services. Finally, it serves as a roadmap for identifying major research gaps and outlines an agenda for future investigations.

The online version contains supplementary material available at 10.1007/s10729-025-09711-z.