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Patents as an Appropriation
Mechanism
URL: http://socrates.berkeley.edu/~scotch/cohenetal.pdf
Growth matters
• First half of the 20th century: real GDP per unit of
labor grew at 2.75%.
• Reminder: the rule of 70.
At growth rate a%, value doubles in about 70/a
years.
• After the first 25 years, output per person was
twice as high, and after 50 years four times as
high.
• In the last quarter of the 20th century, growth has
slowed down, but never below about 1.75%.
300
250
200
Industry R&D
Federal R&D
Total R&D
150
100
50
1995
1988
1981
1974
1967
1960
0
1953
billions of 1996 dollars
R&D Spending: Total, Federal and Industry
250000
200000
Industry R&D
150000
Federal R&D
Total R&D
100000
Domestic
Patent Grants
50000
1995
1988
1981
1974
1967
1960
0
1953
millions of $1996, domestic patent grants
300000
s
R&D Spending and Domestic Patent Grants
Q  F ( L, C , K , T )
Each of L,C,K,T grows. Change per unit time:
Growth Accounting
L, C , K , T
Q  FL L  FC C  FK K  FT T
Wages satisfy:
where FL, FC are the marginal product of L,C
Q  wL L  wC C  FK K  FT T
Rearrange:
wL  FL , wC  FC
Q wL L L wC C C 1


 [ FK K  FT T ]
Q
Q L
Q C
Q
=wage share of GDP Q   L   C  1 F K  F T 
K
T
Q
L
C
Q
=capital share of GDP
Subtract the wage and capital growth shares from growth in GDP to
get the portion of growth not accounted for by L,C. About half!!
R&D, Patents and Productivity
• The growth residual (after accounting for labor and
capital growth) is about half. But is it linked to the
growth in “knowledge”?
Yes, if knowledge is “accumulated R&D.”
Private R&D spending has a bigger effect on GDP
than public spending. Why?
• Rate of return on R&D spending is greater than rate of
return on capital (stock market). Is this what you expect?
Yes, because….
• Suppose the rates of return were the same.
Is R&D spending too high? Too low?
R&D and Patenting
•
R&D spending is an input. Patents are an output.
What is it that we really want to measure?
Can we measure innovation? (no)
Welfare (GDP?) is what we care about in any case.
•
Nevertheless, it might be of interest to record:
1.
2.
3.
4.
•
Total patent grants (not domestic US grants) have grown more or
less commensurately with industrial spending in late 20th century.
(Foreign patent grants grew from 18% to half in postwar.)
Cost of patents is $1m-$2m (1996 dollars)
Rate of return on R&D spending is greater than rate of return on
capital (stock market). Is this what you expect?
Suppose the rates of return were the same.
Is R&D spending too high? Too low?
The value side: Several Methodologies
Patent Values are skewed.
Does skewness matter? What matters for incentives?
Scherer and Harhoff
http://socrates.berkeley.edu/~scotch/skew.pdf
• First two rows: survey evidence
• Next rows: royalty data from technology
licensing offices.
• Penultimate rows: Stock value
• Drugs: Sales
Evidence from Renewal Data:
R(t)
C(t)
time t
What do we learn from renewals?
• Gives a distribution of value of patent rights.
(Distinguish from value of innovation.)
• Most of the value is in the top few patents.
• Half of patents “end” at about year 10.
• Only about 10-15% of R&D spending is
recovered from patent value (24% of private
spending)
Final Methodology: Estimate the effect of patents
on firm’s stock value
• Three regressors that affect firm value:
patent counts, R&D spending, patent citations,
• Should help us distinguish between the value of the
innovation and the value of a patent right.
• Early studies used patent counts and R&D.
The R&D variable reduces the value of the patent right to
¼ its previous value.
• Patent citations are a better predictor of value than patent
counts, but still less good than R&D spending.
when g
K
A
is small
Empirical question: For which types of K is the coefficient g larger?