Small Area Estimation-New Developments and Directions

The purpose of this paper is to provide a critical review of the main advances in small area estimation (SAE) methods in recent years. We also discuss some of the earlier developments, which serve as a necessary background for the new studies. The review focuses on model dependent methods with special emphasis on point prediction of the target area quantities, and mean square error assessments. The new models considered are models used for discrete measurements, time series models and models that arise under informative sampling. The possible gains from modeling the correlations among small area random effects used to represent the unexplained variation of the small area target quantities are examined. For review and appraisal of the earlier methods used for SAE, see Ghosh & Rao (1994).     

The Potential for Increased Trade in Milk and Dairy Products between Canada and the United States under Trade Liberalization

Controversy surrounds the effect of free trade in milk and dairy products between Canada and the United States. A static, nonspatial, synthetic, partial equilibrium model is used to explore this issue. The results show that under any reasonable set of parameter estimates, net trade between Canada and the United States would be small, or zero. Free trade would be accompanied by large welfare losses for the current owners of Canadian milk production quota, but new entrants to the industry would earn more producer surplus under free trade than if they paid the full rental value for production quota under the current supply management policy.     

Multiple equilibria in the dynamics of financial globalization: The role of institutions

Recent research underscores the dual role played by institutions for deciphering the financial globalization – growth nexus. On the one hand, for capital account liberalization to be growth enhancing, a critical level of local institutional quality is needed. On the other hand, increased integration in the global financial system strengthens these countries’ institutions. We argue that this complex relationship may give rise to multiple equilibria in the dynamics of financial global integration: haphazard capital account liberalization may lead to situations where well integrated nations become increasingly better integrated, while poorly integrated nations are left at the margin. To test this hypothesis, we check whether controlling for the quality of institutions eliminates conditional convergence of global financial integration. Our results confirm that growth in financial integration is non-linear, and that this non-linearity disappears once we control for the quality of institutions.     

Cohort versus patient level simulation for the economic evaluation of single versus combination immuno-oncology therapies in metastatic melanoma

Abstract

Background: Model structure, despite being a key source of uncertainty in economic evaluations, is often not treated as a priority for model development. In oncology, partitioned survival models (PSMs) and Markov models, both types of cohort model, are commonly used, but patient responses to newer immuno-oncology (I-O) agents suggest that more innovative model frameworks should be explored.

Objective: A discussion of the theoretical pros and cons of cohort level vs patient level simulation (PLS) models provides the background for an illustrative comparison of I-O therapies, namely nivolumab/ipilimumab combination and ipilimumab alone using patient level data from the CheckMate 067 trial in metastatic melanoma. PSM, Markov, and PLS models were compared on the basis of coherence with short-term clinical trial endpoints and long-term cost per QALY outcomes reported.

Methods: The PSM was based on Kaplan-Meier curves from CheckMate 067 with 3-year data on progression free survival (PFS) and overall survival (OS). The Markov model used time independent transition probabilities based on the average trajectory of PFS and OS over the trial period. The PLS model was developed based on baseline characteristics hypothesized to be associated with disease as well as significant mortality and disease progression risk factors identified through a proportional hazards model.

Results: The short-term Markov model outputs matched the 1–3?year clinical trial results approximately as well as the PSMs for OS but not PFS. The fixed (average) cohort PLS results corresponded as well as the PSMs for OS in the combination therapy arm and PFS in the monotherapy arm. Over the lifetime horizon, the PLS produced an additional 5.95 quality adjusted life years (QALYs) associated with combination therapy relative to ipilimumab alone, resulting in an incremental cost-effectiveness ratio (ICER) of £6,474 per QALY, compared with £14,194 for the PSMs which gave an incremental benefit of between 2.2 and 2.4 QALYs. The Markov model was an outlier (～ £49,000 per QALY in the base case).

Conclusions: The 4- and 5-state versions of the PSM cohort model estimated in this study deviate from the standard 3-state approach to better capture I-O response patterns. Markov and PLS approaches, by modeling state transitions explicitly, could be more informative in understanding I-O immune response, the PLS particularly so by reflecting heterogeneity in treatment response. However, both require a number of assumptions to capture the immune response effectively. Better I-O representation with surrogate endpoints in future clinical trials could yield greater model validity across all models.     

When is human capital a valuable resource? The performance effects of Ivy league selection among celebrated CEOs

We investigate whether and when highly trained human capital constitutes a rent‐sustaining resource. Our study of 444 CEOs celebrated on the covers of major U.S. business magazines found an advantage accruing to graduates of selective universities. Such CEOs led firms with higher and more sustained market valuations. The advantage was strongest for undergraduate programs as these related to the kinds of talent demanded of a CEO. The advantage also was greatest in smaller firms where CEO discretion might be highest and for younger CEOs who may benefit most from college and are less able to appropriate rents. Finally, the advantage accrued to graduates of more recent years, when selective schools had become less socially elitist and increasingly meritocratic, thus favoring human versus social capital. Copyright © 2014 John Wiley & Sons, Ltd.