We wonder if some vegetable becomes too expensive, consumers or even mass retail stores shift to substitutional ones, which makes sense as per economics.We will look at prices in WInter 2017 for three leafy vegetables,lettuce,Chines cabbage and spinach.We’ve picvked these vegetables because lettuce’s price became 4 times in one month due to rainy autumn and typhoon and that supply into Tokyo Ohta decreased to half.
Leafy vegetables : Price influenced by other vegetables?
As we mentioned,the price of lettuce goes up sharply in November and December 2017,which can be also explained by the sudden drop of supply in the market.
You can also see Chinese cabbage price goes up due to less supply, however if you compare that behavior with the ones in Y2015,Y2016 circled in green,you will find it is too steep or even opposite.
If we go to spinach, we will also notice the price up in November, however it looks similar behavior to the one in Y2015,Y2016.
So, We can say people has shifted to buy from lettuce to Chinese cabbage,can’t we? But we could not say spinach becomes expensive due to too high lettuce price.
Anyway, when farmers set the requested retail price by themselves, they may need to consider this facor “alternate vegetables becomes expensive beyond some threshold, demand will shift to the one” which sounds “copula” in statistics.