단계적 회귀분석(Stepwise Regression) 이용한 항공운임 추정과 예측(인천에서 미국의 LA와 독일의 프랑크푸르트 노선)

Abstract

The study is to estimate air freight rates, identify explanatory variables, and forecast future air freight rates. The study adopted the partial adjustment model for setting regression, which is the well-known approach to estimate prices, rates or fares. The study analyzed the statistics of the variables collected from 2006 to 2010 focused on two routes, one from Incheon(Korea) to LA (US) and the other from Incheon(Korea) to Frankfurt(Germany). For the model identification and estimation, the study selected two price references including Dubai crude oil price and US gulf jet fuel price, and conducted the model identification and estimation for each price reference. Among 110 potential explanatory factors, the study selected the operational rates of Korean Air’s cargo business units, the price indexes of Korean stocks, the total volumes of imports to and exports from Korea, and the currency exchange rates. They were identified to be significant factors, influencing the levels of the air freight rates. The operational rates of Korean Air, whose market position is strong enough to influence the whole industry were identified as the most influential factor. Through the stepwise regressions, the study identified the time lagged influences of the different sets of the variables depending on the routes. Also the forecasting accuracies were satisfactory because MAPE and RMSPE of the results were less than 10% except the jet oil case from Incheon to LA.