WIPO Journal - World Intellectual Property Organization
WIPO Journal - World Intellectual Property Organization
WIPO Journal - World Intellectual Property Organization
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164 The <strong>WIPO</strong> <strong>Journal</strong><br />
Q output<br />
P output price<br />
X 1 input factor 1 (land)<br />
X 2 input factor 2 (all other inputs including fertiliser, seeds, and labour)<br />
W 1 price of X 1 (land)<br />
W 2 price of X 2 (other inputs)<br />
Totally differentiating equations (1–6) and expressing the results as relative changes yields equations in<br />
terms of the relative changes and elasticities, the effect of a change in the price of one factor on the quantity<br />
demanded. The solution consists of linear equations expressing these relative changes in endogenous<br />
(internally determined) prices and quantities as functions of the parameters (such as demand and supply<br />
elasticities, elasticity of substitution, factor cost shares) and exogenous shifters. The shift variables, B1<br />
and B2, take particular forms to represent the price and quantity effects of a subsidy on an output or an<br />
input; they take different values, combined with extreme elasticity assumptions, to represent a quota on<br />
an output or an input. Alston and James derived price and quantity effects of subsidies or quotas in terms<br />
of cost shares and elasticities, as reported in Table 3.<br />
Table 3: Price and quantity effects of supply/demand shifters in a two-factor model 29<br />
k 1<br />
k 2<br />
η<br />
ε 1<br />
ε 2<br />
σ<br />
cost share X 1<br />
cost share X 2 such that k 1 + k 2 = 1<br />
elasticity demand for Q (absolute value)<br />
elasticity supply for X 1<br />
elasticity supply for X 2<br />
elasticity substitution between X 1 and X 2<br />
29 Source: Alston and James, “The incidence of agricultural policy” in Handbook of Agricultural Policy 2002.<br />
(2011) 2 W.I.P.O.J., Issue 2 © 2011 Thomson Reuters (Professional) UK Limited