A macro stress test model of credit risk for the Brazilian banking sector

This paper proposes a model to conduct macro stress test of credit risk for the banking sector based on scenario analysis. We employ an original bank-level data set that splits bank credit portfolios in 21 granular categories, covering household and corporate loans. The results corroborate the presence of a strong procyclical behavior of credit quality, and show a robust negative relationship between the logistic transformation of non-performing loans (NPLs) and GDP growth, with a lag response of up to three quarters. The results also indicate that the procyclical behavior of loan quality varies across credit types. This is novel in the literature and suggests that banks with larger exposures to highly procyclical credit types and economic sectors would tend to undergo sharper deterioration in the quality of their credit portfolios during an economic downturn. Lack of sufficient portfolio granularity in macro stress testing fails to capture these effects and thus introduces a source of bias that tends to underestimate the tail losses stemming from the riskier banks in a system.     

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.     

Household Behavior with Imperfect Labor Markets

A household model with differential asset endowments and idiosyncratic transactions costs in accessing labor markets is developed to (1) explain membership of farm households to alternative labor regimes (sellers, employers, or self-sufficient in labor), (2) test for recursivity between production and consumption decisions selectively by labor regime, and (3) identify the determinants of differential labor productivity across labor regimes. The model is applied to a 1994 household survey of the Mexican land reform sector.     

What Do Rental Contracts Reveal About Adverse Selection and Moral Hazard in Rental Housing Markets?

This article examines the pricing of rental contracts for two types of renter households: those who are able to amass a large, up-front security deposit and those with little, or no, security to offer. Empirical tests are presented to suggest that, in dealing with renter households who have little, or no, security to offer, landlords earn at a similar rate of return as lenders who make riskier loans at a high interest rate to borrowers of dubious credit. The analysis suggests that this situation occurs in large part because of the problem of asymmetric information and moral hazard between landlords and renter households regarding the latter's use of the premises.     

Performance hypothesis testing with the Sharpe ratio: The case of hedge funds

As recent research highlights that the Sharpe ratio has a decision theoretic foundation even in the case of asymmetric or fat-tailed excess returns and thus is adequate even for the evaluation of hedge funds, this note provides the first Sharpe ratio based performance analysis of the hedge fund market. Furthermore, it addresses the important practical question whether the choice of hypothesis test used to statistically compare Sharpe ratios can influence an investor’s hedge fund selection process. Our key findings are as follows: (i) Only a small fraction of hedge funds in our large dataset can significantly outperform passive investments in corresponding hedge fund indices. (ii) Especially in the presence of autocorrelated or skewed excess returns, the traditional test of Jobson and Korkie, 1981, Memmel, 2003 tends to overstate the number of significant outperformers and thus provides potentially misleading information for investors. Decision makers are advised to use the bootstrap test of Ledoit and Wolf (2008) allowing robust and more reliable inference.     

Fiscal implications of climate change

Climate change is an externality problem—so the challenges that arise in limiting it and dealing with the effects that remain are largely fiscal. The structure of the problem, however, and the uncertainty which surrounds it, make the design of proper policy responses particularly complex. This paper provides a primer on the fiscal implications of climate change, the aim being to provide a (reasonably) quick and comprehensive overview of the main analytical issues and lessons learned.     

Innovation Aesthetics: The Relationship between Category Cues,Categorization Certainty,and Newness Perceptions

Recent research notes a disconnect between what marketers deem new and innovative versus what consumers actually perceive. Many factors may contribute to this; however, the factor that has significant potential to first attract a consumer to a new product, visual aesthetic design, is investigated in this research. Findings from four studies indicate that if a consumer cannot affix a category label to a new product with certainty, as can happen with innovative aesthetics, a product's newness will be underappreciated and product evaluations will suffer. By utilizing a categorization framework and specifically accounting for the role of categorization certainty, insight into the effects of innovative visual aesthetics and why newness perceptions are inherently subjective, and therefore, potentially hazardous to new product adoption, is provided.