Optimal Management of Soil Quality Stocks and Long-Term Consequences of Land Degradation for Smallholder Farmers in Malawi

While soil degradation has long-term consequences, static models which form the bulk of studies on this topic in Africa, do not account for the inter-temporal dimensions of optimal resource management. This paper used an inter-temporal optimisation framework, which considered soil in a time-dependent resource extraction perspective. We have demonstrated that soil degradation is causing an enormous reduction in productive value of smallholder land in Malawi. Current user cost of soil quality among smallholder farmers, which represents annual loss in productive value of land, was estimated to be US$21 per hectare. Based on this value and land area under smallholder agriculture in Malawi, economic costs of soil degradation among smallholder farmers were estimated to amount to 14% of the agricultural GDP for Malawi. Although smallholder farmers’ current practices are sub-optimal to Steady State solutions, they are above static solutions. This demonstrates that smallholder farmers have some private incentives to invest in the soil quality stock. Smallholder farmers internalise some of the dynamic costs of soil degradation under the current practices. However, a sensitivity analysis on a slightly higher discount rate indicates that SS solutions closely resemble the prevailing smallholder farming practices. This suggests that smallholder farmers may be overexploiting soil quality stock because they have a high time preference. That is, they value the current consumption more than their future consumption and wellbeing. High levels of poverty in Malawi and serious lack of viable alternatives to subsistence farming may be influencing such behaviour. Promoting more viable land use alternatives than subsistence farming and formuling policies that help transform smallholder agriculture into a profitable enterprise will not only increase the cost of degrading the soil, but also encourage farmers to invest in the soil quality stock.     

The hydroelectricity consumption and economic growth in Asian countries - evidence using an asymmetric cointegration approach

ABSTRACT

This study examines the four commonly tested hypotheses in hydroelectricity consumption – economic growth literature for 12 Asian countries. Our results from a recently developed hidden cointegration technique uncover rich and significant relationships between negative and positive components of the variables under consideration. In particular, we find evidence to support the neutrality hypothesis in five countries (Bangladesh, Indonesia, Pakistan, Philippines, and Thailand), the growth hypothesis in four countries (India, Japan, South Korea and Taiwan), and both growth and conservation hypotheses in three countries (China, Malaysia, and New Zealand). These findings suggest that appropriate economic policies should be elaborated on the basis of the country’s specific hydroelectricity consumption–growth nexus. Finally, our new evidence suggests that the lack of stable relationship between hydroelectricity consumption and economic growth documented in previous studies for some of these countries could be due to the failure to properly account for the nonlinearity property in the data.     

Experiments Testing Multiobject Allocation Mechanisms

This paper reports the results of over 130 auctions conducted under controlled conditions to examine the robustness of several auction mechanisms to allocate multiple objects. The simultaneous discrete auction process used by the Federal Communications Commission to allocate Personal Communications licenses was contrasted with a sequential auction and a combinatorial auction over a variety of demand conditions. In test environments created to check only the minimum competency of the procedures, the simultaneous discrete auction process produces highly efficient allocations, approaching levels similar to those found with a continuous form of the auction, and it outperforms a sequential auction. However, in environments created to stress test the procedures, a combinatorial auction outperforms the simultaneous discrete auction.     

How useful are signals? A micro-structure analysis

We analyze how the market processes a signaling event by studying a sample of self-tender offers, events often viewed as signals of firm value. By examining changes in the degree of informed trading, we find asymmetric information costs fall at announcement, remain low throughout the event, and increase at offer expiration. By one month following expiration, informed trading returns to a level not significantly different from that prior to the offer. Higher risk firms have significantly larger declines in information asymmetry during the offer. Increases in information asymmetry persist one month following expiration for firms with lower pre-offer informed trading. (JEL G14, G32)     

Run theorems for low returns and large banks

In this paper, we revisit the issue of bank fragility in the Diamond and Dybvig (J Polit Econ 91:401–419, 1983) model with sequential service and finite traders. We provide a precise condition under which banks are susceptible to a run when the return on investment is low, and we show that sufficiently large banks are always susceptible to a run. One interpretation of the condition is that exposure to runs occurs when desire for consumption smoothing or predictability of preference profiles are relatively high.     

On the formation of interaction networks in social coordination games

There are many situations where two interacting individuals can benefit from coordinating their actions. We examine the endogenous choice of partners in such social coordination games and the implications for resulting play. We model the interaction pattern as a network where individuals periodically have the discretion to add or sever links to other players. With such endogenous interaction patterns we see multiple stochastically stable states of play, including some that involve play of equilibria in the coordination game that are neither efficient nor risk-dominant. Thus the endogenous network structure not only has implications for the interaction pattern that emerges, but it also has a significant impact on the play in the coordination game relative to what would arise if the same interaction network were exogenous.     

A review and validation of overall survival extrapolation in health technology assessments of cancer immunotherapy by the National Institute for Health and Care Excellence: how did the initial best estimate compare to trial data subsequently made available?

Background: Validation of overall survival (OS) extrapolations of immune-checkpoint inhibitors (ICIs) during the National Institute for Health and Care Excellence (NICE) Single Technology Assessment (STA) process is limited due to data still maturing at the time of submission. Inaccurate extrapolation may lead to inappropriate decision-making. The availability of more mature trial data facilitates a retrospective analysis of the plausibility and validity of initial extrapolations. This study compares these extrapolations to subsequently available longer-term data.

Methods: A systematic search of completed NICE appraisals of ICIs from March 2000 to December 2017 was performed. A targeted search was also undertaken to procure published OS data from the pivotal clinical trials for each identified STA made available post-submission to NICE. Initial Kaplan-Meier curves and associated extrapolations from NICE documentation were extracted to compare the accuracy of OS projections versus the most mature data.

Results: The review identified 11 STAs, of which 10 provided OS data upon submission to NICE. The extrapolations undertaken considered parametric or piecewise survival models. Additional data cut-offs provided a mean of 18 months of OS beyond the end of the original data. Initial extrapolations typically under-estimated OS from the most mature data cut-off by 0.4–2.7%, depending on the choice of assessment method and use of the manufacturer- or ERG-preferred extrapolation.

Conclusion: Long-term extrapolation of OS is required for NICE STAs based on initial immature OS data. The results of this study demonstrate that the initial OS extrapolations employed by manufacturers and ERGs generally predicted OS reasonably well when compared to more mature data (when available), although on average they appeared to underestimate OS. This review and validation shows that, while the choice of OS extrapolation is uncertain, the methods adopted are generally aligned with later-published follow-up data and appear appropriate for informing HTA decisions.     

Eurosystem monetary targeting: Lessons from U.S. data

Using a small empirical model of inflation, output, and money estimated on U.S. data, we compare the relative performance of monetary targeting and inflation targeting. The results show monetary targeting to be quite inefficient, yielding both higher inflation and output variability. This is true even with a nonstochastic money demand formulation. Our results are also robust to using a P∗ model of inflation. Therefore, in these popular frameworks, there is no support for the prominent role given to money growth in the Eurosystem's monetary policy strategy.     

Means-Testing the Child Benefit

Improving the distributional impact of transfers may be costly if it reduces labor supply. In this paper we show how effects of changes in the design of the child benefit program can be examined by employing information from behavioral and non-behavioral simulations on micro data. The direct distributional effects are assessed by tax-benefit model calculations, while female labor supply responses to alternative child benefit schemes are simulated under the assumption that choices are discrete. Distributional effects after labor supply responses are also shown. The study confirms that greater targeting of the child benefit is traded against reductions in female labor supply.