Technical efficiency analysis correcting for biases from observed and unobserved variables: an application to a natural resource management project

This article brings together the stochastic frontier framework with impact evaluation methodology to compare technical efficiency (TE) across treatment and control groups using cross-sectional data associated with the MARENA Program in Honduras. A matched group of beneficiaries and control farmers is determined using propensity score matching techniques to mitigate biases stemming from observed variables. In addition, possible self-selection arising from unobserved variables is addressed using a selectivity correction model for stochastic frontiers recently introduced by Greene (J Prod Anal 34:15?C24, 2010). The results reveal that average TE is consistently higher for beneficiary farmers than the control group while the presence of selectivity bias cannot be rejected. TE ranges from 0.67 to 0.75 for beneficiaries and from 0.40 to 0.65 for the control depending on whether biases were controlled or not. The TE gap between beneficiaries and control farmers decreases by implementing the matching technique and the sample selection framework decreases this gap even further. The analysis also suggests that beneficiaries do not only exhibit higher TE but also higher frontier output.     

Economists' Opinions of Economists' Work

A bstract .   Economists' credibility has been waning in recent years. Critics usually cite the profession's preoccupation with abstract reasoning and its focus on seemingly irrelevant topics that hold little interest for individuals outside the discipline. While economic science has enormous potential for improving living standards, the profession's adverse reputation is indicative of a discipline seemingly void of any social contribution. This article presents the results of a recently conducted survey of professional economists. The survey was undertaken to ascertain economists' opinions of their own professional work, including the progress of economic research, its usefulness for society, and factors that determine the publication of that research.     

Economic evaluation of BST-CarGel as an adjunct to microfracture vs microfracture alone in knee cartilage surgery

Objectives:

Knee cartilage damage is a common cause of referral for orthopedic surgery. Treatment aims to reduce pain and symptoms by repairing cartilage. Microfracture, the current standard of care, yields good short-term clinical outcomes; however, treatment might fail after 2–3 years. A Chitosan-Beta glycerolphosphate-based medical device (BST-CarGel) is used as an adjunct to microfracture and demonstrates improvements in quantity and quality of repaired tissue, potentially reducing the risk of treatment failure. This study aimed to establish the economic value of BST-CarGel vs microfracture alone in knee cartilage repair from the societal perspective, using Germany as the reference market.

Methods:

A decision tree with a 20-year time-horizon was constructed, in which undesirable clinical events were inferred following initial surgery. These events consisted of pain management, surgery, and total knee replacement. Clinical outcomes were taken from the pivotal clinical trial, supplemented by other literature. Data and assumptions were validated by a Delphi panel. All relevant resource use and costs for procedures and events were considered.

Results:

In a group of patients with all lesion sizes, the model inferred that BST-CarGel yields a positive return on investment at year 4 (with 20-year cumulative cost savings of €6448). Reducing the incremental risk of treatment failure gap between the device and microfracture by 25–50% does not alter this conclusion. Cost savings are greatest for patients with large lesions; results for patients with small lesions are more modest.

Limitations:

Clinical evidence for microfracture and other interventions varies in quality. Comparative long-term data are lacking. The comparison is limited to microfracture and looks only at costs without considering quality-of-life.

Conclusion:

BST-CarGel potentially represents a cost-saving alternative for patients with knee cartilage injury by reducing the risk of clinical events through regeneration of chondral tissue with hyaline characteristics. Since the burden of this condition is high, both to the patient and society, an effective and economically viable alternative is of importance.     

Healthcare costs for Crohn’s disease patients treated with infliximab: a propensity weighted comparison of the effects of treatment adherence

Objective:

The objective for the research was to evaluate the direct healthcare costs for Crohn’s disease (CD) patients categorized by adherence status.

Methods:

Adult patients with ≥1 claim for infliximab and ≥2 claims for CD who were continuously insured for 12 months before and after their first infliximab infusion (index date) were identified in a 2006–2009 US managed care database. Patients were excluded if they had rheumatoid arthritis claims, received infliximab billed as a pharmacy benefit, or received another biologic drug. Patients were categorized as being either adherent or intermittently adherent to infliximab using a pre-defined algorithm. Total and component direct costs, CD-related costs, rates of surgery, and days of hospitalization were estimated for the 360-day post-index period. Propensity weighted generalized linear models were used to adjust the cost estimates for potential confounding variables.

Results:

The total propensity weighted cost for infliximab adherent patients was $40,425 (95% CI?=?[$38,686, $42,242]), compared to $41,082 (95% CI?=?[$38,163, $44,223]) for the intermittently adherent (p?=?0.71). However, adherent patients had lower total direct medical costs, exclusive of infliximab, that were $13,097 (95% CI?=?[$12,141, $14,127]) compared with $20,068 (95% CI?=?[$17,676, $22,784]) for intermittently adherent patients as a result of substantially lower hospital and outpatient costs (p?Conclusions:

Greater drug-related costs for infliximab adherent patients were offset by lower costs from hospitalization and outpatient visits. These findings indicate that adherent patients have improved clinical outcomes, at a similar aggregate cost, than patients who are only intermittently adherent to therapy.     

The 1997 Asian Currency Crisis,Financial Linkages,and the Monetary Policy of Japan

The evidence is examined that excessively liberal monetary policy by the Bank of Japan, before and after the financial collapse of Japan in 1992, may have led other East Asian economies into “over‐borrowing” and speculative investments, prior to the currency crisis in 1997–98. The authors test for cointegration and Granger causality between Japanese money supply M1 and the domestic investment of eight East Asian economies and Australia. US and German money supplies are also used as a benchmark. There is strong evidence that there are long‐ and short‐run causal relationships between the Japanese money supply and the domestic investment of the Asian crisis‐inflicted economies prior to 1997.     

Predicting IJVs＇ effectiveness based on their autonomy levels and the characteristics of their parent companies

Separate research streams have identified relationships between IJV autonomy and IJV effectiveness, and between functional/dysfunctional parent-company differentiation and IJV effectiveness. This study attempts to integrate these two literature streams by examining how these two sets of independent variables interact in terms of predicting IJV effectiveness. Results partially support our hypotheses that the autonomy-effectiveness relationship is less positive with greater functional differentiation and more positive with greater dysfunctional differentiation. The results provide strong support for our hypotheses that activities closer to the local operating environment will influence these relationships such that autonomy becomes more important to effectiveness when an activity has strong local ties.     

Collateral equilibrium,I: a basic framework

Much of the lending in modern economies is secured by some form of collateral: residential and commercial mortgages and corporate bonds are familiar examples. This paper builds an extension of general equilibrium theory that incorporates durable goods, collateralized securities, and the possibility of default to argue that the reliance on collateral to secure loans and the particular collateral requirements chosen by the social planner or by the market have a profound impact on prices, allocations, market structure, and the efficiency of market outcomes. These findings provide insights into housing and mortgage markets, including the subprime mortgage market.     

The Middle Class Consensus and Economic Development

A middle class consensus is defined as a high share of income for the middle class and a low degree of ethnic divisons. The paper links a middle class consensus to resource endowments, along the lines of the provocative thesis of Engerman and Sokoloff (1997 and 2000). This paper exploits this association using tropical resource endowments as instruments for inequality. A higher share of income for the middle class and lower ethnic divisions are associated with higher income and higher growth, as well as with more education, better health, better infrastructure, better economic policies, less political instability, less civil war and ethnic minorities at risk, more social modernization and more democracy.     

Undergraduate Coursework in Economics: A Survey Perspective

Survey results from a large sample of economics departments describe offerings for principles courses, coursework requirements for economics majors, and program augmentations such as capstone courses, senior seminars, and honors programs. Findings are reported for all institutions, and institutions are subdivided into six different categories based on public or private control and the highest economics degree offered. The coursework required for the economics major typically consists of ten courses, five in a required core and five electives. The most conspicuous curriculum change over the past 30 years is the rise of econometrics as a required course, now mandatory at about half of major programs. The authors estimate that about 40 percent of students who matriculate as first-year undergraduates take at least one economics course before they leave.