Demand forecasting of button mushrooms using qualitative and quantitative methods at PT. S

Indonesia is one of the countries with an extraordinary natural wealth of plants, one of which is mushroom plants. Button mushroom is one type of mushroom that most people favour. PT. S is a company that produces button mushroom products. The company performs demand forecasting using qualitative methods to fulfil consumer demand, benefiting production, raw material, and planting planning. This research aimed to compare the result of demand forecasting for 2021 by the company and demand forecasting using the ARIMA method as quantitative forecasting. The best ARIMA model was ARIMA (1,1,1) with a p-value of 0.000 and an MSE of 1.32. The results of demand forecasting using the ARIMA method were closer to the actual data than that of by the company. The total actual sales data from January - April 2021 is 150,958 kg. The difference between the total actual sales data and demand forecasting using the qualitative method is 2,277 kg, meanwhile, the difference between the total actual sales data and demand forecasting using the ARIMA method is 596 kg.