11. 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
Equation3: Demand equation (price determination) model
log !"#$!!" = !! ∗ log !"##$!!" + !! ∗ log!(!"##$%!!! ) + !! ∗ ! + !! + !!"
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
variable. Explanatory variable
操作変数(Instrumental
Variable)
is supply quantity, currency rate and time trend.
Since
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。
the price is determined by total supply in the market, the total supply amount
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
12. 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)
