46 research outputs found
THE UNITED STATES IN THE GLOBAL SOYBEAN MARKET: WHERE DO WE GO FROM HERE?
This study applies the concept of a dynamic dominant-firm oligopoly model to the international soybean market. It has been suggested that the international soybean market should be viewed as an oligopoly among exporting nations. Consistent with Gaskins (1971) dynamic dominant firm model, our results indicate that the current U.S. loan deficiency-payment prices and their predecessors created an environment in which smaller (fringe) exporters could prosper and expand. The reduction of U.S. market share is thus a logical outcome of an "optimally managed decline" a la Gaskins. The study finds U.S. market share to decline at a reducing rate and predicts U.S. market share eventually to stabilize, given the expanding international market for soybeans and products. Recognition of the structure of international soybean market has policy implications for the 2002 farm program as the classic dominant firm model suggests.Crop Production/Industries, International Relations/Trade,
Market Forces and Price Ceilings: A Classroom Experiment
The effect of price controls on competitive equilibrium is a standard topic in many undergraduate economics courses. This classroom experiment demonstrates the effect of rent control (price ceilings) on the market for apartments. As participants in the experiment, students experience the effect of a price ceiling as buyers (renters) and sellers (landlords). The classroom-posted offer market exhibits a shortage under a binding price ceiling. Further, we explore a secondary response to rent control. When given the opportunity, landlords lower the quality of the apartments by reducing maintenance expenditures under the price ceiling, thus moving the market back to equilibrium. Since many students are themselves renters, they should relate to changes in quality due to lower maintenance by landlords. This experiment will stimulate discussion on market forces and on public policy aimed at restricting prices.
Strategic Manipulation of Pollution Permit Markets: An Experimental Approach
In this paper we employ experimantal economic methods to examine the effect of market structure on the use of marketable emmisions permits. In particular, we ask whether firms can strategically manipulate a product market using marketable emissions permits. Subjects participate in two markets, a permit market and a product market. They use permits to reduce the cost of production of the final goods that they sell in the product market. Four treatments are used to test the effects of initial permit allocation and market structure. The first two treatments explore "simple" manipulation. In this case firms are all price takers in the product market but must compete both in the permit and final product markets, thus opening the potential use of permits as a form of market predation. Results show that in a market with one dominant firm and a number of fringe firms, strategic manipulation occurs repeatedly in the laboratory as the dominant firm uses licenses in an inefficient manner in order to minimize its costs, increase its profits and exclude rivals in the product market. Further these finding indicate, that far from improving market efficiency and decreasing the cost to society of pollution control, implementation of tradable permit markets where there are firms in a position of market power may decrease efficiency.
Patient information leaflets (PILs) for UK randomised controlled trials : a feasibility study exploring whether they contain information to support decision making about trial participation
Peer reviewedPublisher PD
Adding 6 months of androgen deprivation therapy to postoperative radiotherapy for prostate cancer: a comparison of short-course versus no androgen deprivation therapy in the RADICALS-HD randomised controlled trial
Background
Previous evidence indicates that adjuvant, short-course androgen deprivation therapy (ADT) improves metastasis-free survival when given with primary radiotherapy for intermediate-risk and high-risk localised prostate cancer. However, the value of ADT with postoperative radiotherapy after radical prostatectomy is unclear.
Methods
RADICALS-HD was an international randomised controlled trial to test the efficacy of ADT used in combination with postoperative radiotherapy for prostate cancer. Key eligibility criteria were indication for radiotherapy after radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to radiotherapy alone (no ADT) or radiotherapy with 6 months of ADT (short-course ADT), using monthly subcutaneous gonadotropin-releasing hormone analogue injections, daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as distant metastasis arising from prostate cancer or death from any cause. Standard survival analysis methods were used, accounting for randomisation stratification factors. The trial had 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 80% to 86% (hazard ratio [HR] 0·67). Analyses followed the intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and ClinicalTrials.gov, NCT00541047.
Findings
Between Nov 22, 2007, and June 29, 2015, 1480 patients (median age 66 years [IQR 61–69]) were randomly assigned to receive no ADT (n=737) or short-course ADT (n=743) in addition to postoperative radiotherapy at 121 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 9·0 years (IQR 7·1–10·1), metastasis-free survival events were reported for 268 participants (142 in the no ADT group and 126 in the short-course ADT group; HR 0·886 [95% CI 0·688–1·140], p=0·35). 10-year metastasis-free survival was 79·2% (95% CI 75·4–82·5) in the no ADT group and 80·4% (76·6–83·6) in the short-course ADT group. Toxicity of grade 3 or higher was reported for 121 (17%) of 737 participants in the no ADT group and 100 (14%) of 743 in the short-course ADT group (p=0·15), with no treatment-related deaths.
Interpretation
Metastatic disease is uncommon following postoperative bed radiotherapy after radical prostatectomy. Adding 6 months of ADT to this radiotherapy did not improve metastasis-free survival compared with no ADT. These findings do not support the use of short-course ADT with postoperative radiotherapy in this patient population
Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial
Background
Previous evidence supports androgen deprivation therapy (ADT) with primary radiotherapy as initial treatment for intermediate-risk and high-risk localised prostate cancer. However, the use and optimal duration of ADT with postoperative radiotherapy after radical prostatectomy remains uncertain.
Methods
RADICALS-HD was a randomised controlled trial of ADT duration within the RADICALS protocol. Here, we report on the comparison of short-course versus long-course ADT. Key eligibility criteria were indication for radiotherapy after previous radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to add 6 months of ADT (short-course ADT) or 24 months of ADT (long-course ADT) to radiotherapy, using subcutaneous gonadotrophin-releasing hormone analogue (monthly in the short-course ADT group and 3-monthly in the long-course ADT group), daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as metastasis arising from prostate cancer or death from any cause. The comparison had more than 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 75% to 81% (hazard ratio [HR] 0·72). Standard time-to-event analyses were used. Analyses followed intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and
ClinicalTrials.gov
,
NCT00541047
.
Findings
Between Jan 30, 2008, and July 7, 2015, 1523 patients (median age 65 years, IQR 60–69) were randomly assigned to receive short-course ADT (n=761) or long-course ADT (n=762) in addition to postoperative radiotherapy at 138 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 8·9 years (7·0–10·0), 313 metastasis-free survival events were reported overall (174 in the short-course ADT group and 139 in the long-course ADT group; HR 0·773 [95% CI 0·612–0·975]; p=0·029). 10-year metastasis-free survival was 71·9% (95% CI 67·6–75·7) in the short-course ADT group and 78·1% (74·2–81·5) in the long-course ADT group. Toxicity of grade 3 or higher was reported for 105 (14%) of 753 participants in the short-course ADT group and 142 (19%) of 757 participants in the long-course ADT group (p=0·025), with no treatment-related deaths.
Interpretation
Compared with adding 6 months of ADT, adding 24 months of ADT improved metastasis-free survival in people receiving postoperative radiotherapy. For individuals who can accept the additional duration of adverse effects, long-course ADT should be offered with postoperative radiotherapy.
Funding
Cancer Research UK, UK Research and Innovation (formerly Medical Research Council), and Canadian Cancer Society
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Market accessibility and the entry decision: A theoretical and experimental examination.
The role of market accessibility and entry is the central theme of this dissertation. Two theoretical models of oligopoly theory are examined in a controlled laboratory market setting. Experimental testing of Contestability Theory is extended beyond the natural monopoly case and a "safe haven" provides subjects with a viable alternative to the "contestable" market. Evidence reported supports the conclusion that the contestable market is robust to the introduction of the alternate market. The theory of Bertrand-Edgeworth duopoly is explored from a game theoretic perspective with special attention to buyer queuing rule assumptions. Experimental evidence underscores sensitivity of market outcomes to the queuing rule adopted. The presence of excess capacity relative to market demand tends to push theoretical Bertrand-Edgeworth equilibria toward competitive levels. This result is substantiated by experimental evidence and is independent of the queuing rule assumed. The similarity between the Bertrand-Edgeworth excess capacity case and a contestable natural monopoly market is investigated. The presence of excess capacity/potential entrants is shown to exert more downward pressure on observed laboratory market prices than the presence of additional competitors alone. This result is at odds with the traditional Structure-Conduct-Performance Paradigm. A herfindahl index calculated from experimental results has almost no power to predict market outcome
Contestability in the Presence of an Alternate Market: An Experimental Examination
Most earlier experimental tests of the contestable market hypothesis assume a zero opportunity cost of entry. This design feature makes interpretation of results in terms of entry behavior problematic. The experimental study that I report tests contestability with the addition of an alternative market that yields a positive profit with certainty. This safe haven operationalizes a positive opportunity cost of entry. Hit-and-run entry is observed in the experiments. Adjusted mean prices are not significantly different from the zero opportunity cost case. Two methodological questions are also examined. In one treatment, sellers' price offers are allowed only in $0.25 increments. The simplification of the sellers' decision space makes collusive arrangements more probable. Secondly, market outcomes using human subject buyers are compared with outcomes from experiments with computer-simulated demand. The disciplining effect of human subject buyers results in market prices that converge to competitive levels more quickly.
Bertrand-Edgeworth Competition in Experimental Markets.
The Bertrand-Edgeworth model describes competition among price setting sellers with production capacity constraints. The authors report on laboratory experiments that permit evaluation of different theories of Bertrand-Edgeworth competition: competitive pricing, Edgeworth cycles in prices, mixed strategy Nash equilibrium pricing, and tacit collusion. Each of the theories helps to explain some aspects of the data. However, none of these theories are completely consistent with the data. In relative terms, the Edgeworth cycle theory provides better predictions of key aspects of the data than the other theories. Coauthors are Stephen Rassenti, Stanley S. Reynolds, and Vernon L. Smith. Copyright 1994 by The Econometric Society.
Valuing self-protection: income and certification effects for safe rooms
Survey data from Tulsa, Oklahoma residents are used to examine individual valuations of safe rooms. The study utilises two measures of individual valuations, the maximum willingness to pay (WTP) and willingness to accept (WTA) for safe rooms. The primary research questions are concerned with whether the willingness to pay measure exhibits income effects and whether certification standards make the safe room investment more desirable. The main findings can be summarised as follows. The mean willingness to pay for a safe room was 600 on average. There is no direct income effect in that respondents' stated willingness to pay does not bear a statistically significant relationship to reported income. There is evidence of a secondary income effect in that willingness to pay elicited from attendees of a suburban parade of homes was $731 higher than attendees of an urban parade of homes. A mortgage payment-based WTA measure yields mean valuations of the safe room more than three times higher than the lump sum WTP valuation.Safe room, willingness to pay, willingness to accept, valuation, certification,