Forecasting the Consumer Price Index in Palembang Using Golden Section Optimization of the Double Exponential Smoothing Method Siti Nurhaliza, Tri Febriani Putri, Tri Wahyuni, Fitri Maya Puspita, Sisca Octarina
Sriwijaya University
Abstract
The consumer price index (CPI) is a reliable indicator that reflects overall economic conditions and measures the rate of inflation or increase. Changes to the CPI occur monthly and yearly, reflecting the level of inflation or deflation of goods and services. This research aims to optimize parameters and forecast the CPI in Palembang City for the next three periods. The study utilized the Consumer Price Index data from January 2014 to September 2023 in Palembang City. The research methodology utilized the Double Exponential Smoothing method with parameter optimization, using the Golden Section method. The values for 𝛼- and 𝛾- were obtained through optimization using the Golden Section method, yielding 0.9957141 and 0.0127842, respectively. The results of research on the application of Golden Section optimization to Holt^s Double Exponential Smoothing on Consumer Price Index data in Palembang City for the period of October 2023 through December 2023, which are successively 115.059, 115.010, and 114.961 with an MAPE value of 0.8059%.
Keywords: Forecasting, Consumer Price Index, Double Exponential Smoothing, Golden Section
