Import Unit Value Index 2018

The import commodity price index in general is a figure of the development of Indonesia's imported commodity prices per unit weight (kg). The import commodity price index is used, among others, to calculate GDP at constant prices, especially in the import component and to calculate trade exchange rates by comparing developments in the commodity and export price index. The import price index is compiled based on the calculation of the price index according to 8-digit Harmonized System (HS) code, then aggregated and presented in the 2-digit HS code and the larger group of commodities 21 sections HS.Some problems in the preparation of the import price index include heterogeneity and low accuracy of data, as well as changes in the quality of imported goods. Heterogeneity is caused by differences in country of origin and types of specific items that are very diverse. Poor accuracy of import data is mainly due to errors in recording in import documents. Changes in the value of the index are not only caused by increases in the price of goods, but also because there is a change in quality that causes the price of the goods to increase. The 2018 import commodity price index uses the 2013 base year (2013 = 100). Commodity prices are calculated by dividing the CIF value (USD) by its weight (kg). Price data in a group of 8-digit HS may vary widely and contain outliers.Outlier detection can be done through the grafh (boxplot method) and the statistic cook's distance results from the regression model of the value and weight. Outliers will be deleted to reduce heterogeneity. The homogeneous data will be calculated for the median value then compared with the median in the base year, the comparison is an 8-digit HS commodity price index. The homogeneity of the data is measured from the interquartile range (IQR) which its value is below one.