IAES International Journal of Artificial Intelligence (IJ-AI) Vol. 12, No. 1, March 2023, pp. 496~504 ISSN: 2252-8938, DOI: 10.11591/ijai.v12.i1.pp496-504  496 Journal homepage: http://ijai.iaescore.com Forecasting the number of dengue fever based on weather conditions using ensemble forecasting method Mursyidatun Nabilah, Raras Tyasnurita, Faizal Mahananto, Wiwik Anggraeni, Retno Aulia Vinarti, Ahmad Muklason Department of Information Systems, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia Article Info ABSTRACT Article history: Received Oct 1, 2021 Revised Oct 11, 2022 Accepted Oct 25, 2022 Dengue fever is still a crucial public health problem in Indonesia, with the highest case fatality rate (CFR) is 1.01% in East Java, Malang Regency. One of the solutions to control the death rate and cases is to forecast the cases number. This study proposed ensemble forecasting that build from several penalized regressions. Penalized regressions are able to overcome linear regression analysis’ shortcomings by using penalty values, that will affect regression’s coefficient, resulting on regression model with a slight bias in order to reduce parameter estimations and prediction values' variances. Penalized regressions are evaluated and built as ensemble forecasting method to minimize the shortcomings of other existing model, so it could produce more accurate values comparing to single penalized regression model. The result showed that the ensemble model `consists of smoothly clipped absolute deviation (SCAD) and Elastic-Net is sufficient to capture data patterns with root mean squared error (RMSE) 6.38. Keywords: Dengue fever Dengue forecast Ensemble forecasting This is an open access article under the CC BY-SA license. Corresponding Author: Wiwik Anggraeni Department of Information Systems, Institut Teknologi Sepuluh Nopember Sukolilo, Surabaya, Jawa Timur 60111, Indonesia Email: wiwik@is.its.ac.id 1. INTRODUCTION Dengue fever is a dangerous infectious disease whose cases have steadily increased over years. Dengue fever is caused by a virus that is in the saliva of Aedes mosquito that injects human body parts that varies from mild into severe conditions [1], [2]. As stated from Epidemiological data and Surveillance Center, Ministry of Health, Indonesia, in Indonesia, dengue fever is still a crucial problem, this is because the number of infections and the area of distribution is increasing along with the increase in mobility and population density. Based on the Ministry of Health Republic of Indonesia’s data, in 2019, the case fatality rate (CFR) of dengue fever showed a value of 0.67% on a national scale. CFR is obtained from the proportion of deaths to all reported cases. A province is said to have a high CFR if it exceeds 1%. One of the provinces that has a high CFR is East Java with 1.01%. Based on the Malang Regency Health Office, Malang Regency is the area with the highest number of cases and deaths from dengue fever in East Java in 2019, therefore efforts are needed to control the death rate from dengue fever in Malang. To control the mortality rate in Malang Regency, one of the efforts is to predict the number of dengue fever cases in the future, one of the research conducted is building a model to forecast so that the parties in charge could take steps and arrange policies to minimize the increase in cases and mortality rates. Several forecasts related to dengue fever have been carried out by utilizing weekly or monthly number of cases [3]–[5]. Based on the previous research, there is a fairly high correlation between the number of cases of dengue fever with rainfall, temperature [6], and humidity [7].