Co-Kriging Method Performance in Estimating Number of COVID-19 Positive Confirmed Cases in East Java Province

Abstract

An increased rate of COVID-19 confirmed cases since the beginning of 2020 led World Health Organization (WHO) to finally declare COVID-19 as global pandemic on March 12th, 2020. COVID-19 in Indonesia was first confirmed on March 2nd, 2020, and it has quickly spread to many regions in Indonesia. East Java, which is one of the affected provinces also experienced a significant increase in confirmed cases. The number of positive confirmed cases increased to higher level at the end of June and the beginning of July 2020, and then it led East Java to become the province with the highest number of confirmed cases in Indonesia during the period. Based on these problems, it is necessary to estimate the number of confirmed cases in several cities, such as Sidoarjo, Gresik, Pasuruan, Lamongan, Tuban, Malang, Sampang, Sumenep, and Mojokerto using co-kriging method. This study specifically contributed in the performance analysis of co-kriging in the estimation of the number of COVID-19 cases. The use of co-kriging is suitable with the pattern of the spread of COVID-19 cases, which also emphasized the rapid spread around the area of confirmed cases. It was based on the number of confirmed cases as primary variable and the number of suspect cases as secondary variable using updated data on July 21st, 2020. The result showed MAPE value of 18.17%, which is in the range of 10%-20%. It means that co-kriging has good performance in the COVID-19 cases estimation in East Java.