Growth equation (equation2) has log of supply quantity per license as the dependent variable. Independent variable is log of the smolt input per license of two years before. Basically this equation describes that how many percentage of salmon is going to be produced when the smolt input is increased by 1%. Combining these above two equations, it is possible to see the effect of the price of farmed salmon in year t-3 on the supply quantity in year t. 価格決定モデル
価格は供給量と為替レートによって決定される Demand equation (equation3) has price of farmed salmon as the dependent variabl 操作変数 e (I . n E stxpl ru a mna e t n ory tal Vva a ri ri a a bl bl e e ) is supply quantity, currency rate and time trend.
Since the price is determined by total supply in the market, the total supply am 養殖場１ライセンス当たりに発生している過剰生産量を使用 ount 。 is used in here instead of supply per license. Currency rate is the real rate between France and Norway. Because France is the biggest importer of Norwegian Farmed salmon over time, the demand of France has significant effect on the price
library(plm) growm <- ‐ log(qpl) ~ log(lag(ipl,2)) ＃二年前の稚魚の数から今年の供給量 growthmodel <- ‐ plm(growm, data = salmon, model ="random") summary(inputmodel)
inputm <- ‐ log(ipl) ~ lag(log(price),1) + t ＃稚魚の数の決定モデル idmodel <- ‐ plm(inputm, data = salmon, model="random") summary(idmodel)
supm <- ‐ log(price) ~ log(rate) + t + log(qpl) | log(qpl) + log(epl) + log(rate) + t ＃価格決定モデル supmodel <- ‐ plm(supm, data = salmon, model="random", random.method="amemiya") summary(supmodel)