I'm trying to analyze export & import data by countries & their partners in UN Comtrade. As a check, I tried extracting data between China and US for one commodity = 850120. My assumption was export data as reported by China to US and import data as reported by US from China would be equal. But it doesn't seem so.
China says it exported "27,385,806" and US says it imported "61,328,903". Would anybody know why there is a difference? My assumption is both are in USD. If that's not the case, where can I find what unit was used?
Here is the full data and this is the link I used. 156 is country code for China and 842 is for US. If you reverse them (between "r" - reported by and "p" - partner country), you can get the data for the opposite flow https://comtrade.un.org/api/get?r=156&px=HS&ps=2017&p=842&max=5000&freq=A&cc=840682&type=C&fmt=json