Papers by Elizabeth Nolan
Intellectual Property Rights (IPR) regimes for plant breeding are generally justified on the basi... more Intellectual Property Rights (IPR) regimes for plant breeding are generally justified on the basis that they encourage innovation. Introduction of IPR regimes for plant varieties in the United States has led to increased concentration, but it is less clear whether IPRs have promoted useful innovation, as measured by productivity of available corn hybrids. There are difficulties in finding a satisfactory measure of innovation in plant breeding, and in this paper we propose a procedure. Results from the annual corn hybrid trials conducted by 11 US universities over the 20 years from 1990 to 2009, at 365 separate locations in the 11 states, have been collated. This set of unbalanced panel data for grain corn hybrid trials has been used in a fixed effects model to estimate a production function for corn and the contribution to yield of the genetic characteristics of the corn hybrids. The Hausman Taylor estimator is then used to separate out the contribution of GM traits. Because the dat...
An argument in favor of the development of genetically modified (GM) hybrids is that their presen... more An argument in favor of the development of genetically modified (GM) hybrids is that their presence is considered to be risk decreasing., and hence, insurance premiums for US corn growers who plant approved hybrids have been reduced. In this study we investigate, using a large set of experimental data, whether the presence in a corn hybrid of various combinations of GM traits is likely to affect production variability and downside risk. We estimate a heteroskedastic production function that allows for the variance of yield to change with the level of inputs, and use the residuals of the mean function to estimate the marginal effect of each input on variance and skewness of yield. The results show that the presence of most combinations of GM traits leads to an increase in both yield variability and downside risk.
There is evidence of an increase in market concentration and in the importance of private plant b... more There is evidence of an increase in market concentration and in the importance of private plant breeding in the seed industry following the widespread adoption of Intellectual Property Rights regimes for the industry in the developed world. We use data from the US Patent and Trademark Office, US Plant Variety Protection Office and various European Plant Variety Protection databases to estimate the extent of these changes in the seed corn industry.
Australian Journal of Agricultural and Resource Economics, 2013
We measure the relationship between clean prices of individual lots of wool sold at auction and a... more We measure the relationship between clean prices of individual lots of wool sold at auction and a range of characteristics of the raw wool. Based on the data for 111,440 fleece lots sold in the 2008-2009 auction season, five hedonic models are estimated to determine the premiums and discounts associated with each wool characteristic in five micron categories. Several wool characteristics exhibited significant nonlinear relationships, and therefore, joint density functions were assessed where appropriate. The results indicate that fibre diameter has the greatest influence on price in all markets. Brand contamination, higher levels of unscourable colour and vegetable matter contamination were found to negatively influence price.
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... Sydney, by telephone on (02) 9351 2574, fax on 9351 4953, or email at either F.Ahmadi@agec. u... more ... Sydney, by telephone on (02) 9351 2574, fax on 9351 4953, or email at either F.Ahmadi@agec. usyd.edu.au or [email protected] ... to note that much of the recent research into economics education has been driven by the premise that enrolments in economics majors were, and ...
American Journal of Agricultural Economics, 2013
This paper investigates selectivity bias issues arising in the productivity evaluation of biotech... more This paper investigates selectivity bias issues arising in the productivity evaluation of biotech hybrids, with an application to GM corn yield. The analysis is applied to experimental data on Wisconsin corn yields covering the period 1990-2010. Relying on a "Heckman-like" factor that accounts for selectivity, the analysis uncovers evidence of selection bias. It indicates that some of the observed yield advantage associated with GM hybrids is contributed by their conventional genes. This stresses that, even after the widespread adoption of GM corn in the US, traditional breeding still plays an important role in productivity improvements for corn. We also document how rising market concentration of biotech firms has contributed to increasing selectivity bias in corn yield. Our results suggest that current patenting laws may not appropriately differentiate between GM genes and conventional genes.
We estimate a hedonic pricing model to quantify the relationship between clean price of lots of w... more We estimate a hedonic pricing model to quantify the relationship between clean price of lots of wool and individual lot characteristics for all superfine, fine, medium and broad wool types. We expand on existing literature by controlling for key macroeconomic conditions at the time of sale and are able to examine the longer term trend in global demand for wool by utilizing data over a number of selling seasons. Our results indicate fibre diameter, strength, breed group, vegetable matter base and fleece contamination play a key role in the purchase decision. Premiums accrue for finer, strong wool which has been grower classed, while discounts have been identified for wool tainted by branding contamination, unscourable colour or the presence of skin pieces. Key market conditions such as world economic growth, price of substitutes and exchange rates with key trading partners have been found to significantly affect Australia’s competitiveness in the global market for wool.
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Papers by Elizabeth Nolan