Knowledge that Transforms

The publication of Daniel Kahneman's book, Thinking, Fast and Slow, is a major intellectual event. The book summarizes, but also integrates, the research that Kahneman has done over the past forty years, beginning with his path-breaking work with the late Amos Tversky. The broad theme of this research is that human beings are intuitive thinkers and that human intuition is imperfect, with the result that judgments and choices often deviate substantially from the predictions of normative statistical and economic models. In this review, I discuss some broad ideas and themes of the book, describe some economic applications, and suggest future directions for research that the book points to, especially in decision theory.

Abhijit Banerjee and Esther Duflo offer a coherent vision for an economics of poverty and antipoverty policy. Their economics is grounded in an effort to understand the economic and psychological complexities in the lives of poor people, informed by social experiments and field observations. Their preferred policies entail small reforms at the margin, also informed by experiments—specifically randomized control trials. While the book provides some interesting insights, I question how far its approach will get us in fighting global poverty.

In the United States, health care technology has contributed to rising survival rates, yet health care spending relative to GDP has also grown more rapidly than in any other country. We develop a model of patient demand and supplier behavior to explain these parallel trends in technology growth and cost growth. We show that health care productivity depends on the heterogeneity of treatment effects across patients, the shape of the health production function, and the cost structure of procedures such as MRIs with high fixed costs and low marginal costs. The model implies a typology of medical technology productivity: (I) highly cost-effective “home run” innovations with little chance of overuse, such as anti-retroviral therapy for HIV, (II) treatments highly effective for some but not for all (e.g., stents), and (III) “gray area” treatments with uncertain clinical value such as ICU days among chronically ill patients. Not surprisingly, countries adopting Category I and effective Category II treatments gain the greatest health improvements, while countries adopting ineffective Category II and Category III treatments experience the most rapid cost growth. Ultimately, economic and political resistance in the United States to ever-rising tax rates will likely slow cost growth, with uncertain effects on technology growth.

All economists should be conversant with “what happened?” during the financial crisis of 2007–09. We select and summarize sixteen documents, including academic papers and reports from regulatory and international agencies. This reading list covers the key facts and mechanisms in the build-up of risk, the panics in short-term-debt markets, the policy reactions, and the real effects of the financial crisis.

A new meta-field of “forensic economics” has begun to emerge, uncovering evidence of hidden behavior in a variety of domains. Examples include teachers cheating on exams, road builders skimping on materials, violations of U.N. sanctions, unnecessary heart surgeries, and racial biases in employment decisions, traffic stops, auto retailing, and even sports judging. In each case, part of the contribution of economic analysis is in uncovering evidence of wrongdoing. Although research questions differ, forensic economic work shares commonalities in approaches and limitations. This article seeks to draw out the common threads, with the hope of stimulating further research across fields.

This paper reports some of the recent developments in the econometric analysis of semimartingales estimated using high frequency financial returns. It describes a simple yet powerful methodology to decompose asset returns sampled at high frequency into their base components (continuous, small jumps, large jumps), determine the relative magnitude of the components, and analyze the finer characteristics of these components such as the degree of activity of the jumps. We incorporate to effect of market microstructure noise on the test statistics, apply the methodology to high frequency individual stock returns, transactions and quotes, stock index returns and compare the qualitative features of the estimated process for these different data and discuss the economic implications of the results.

Financial advice could play an essential role in well-functioning markets for retail financial products, given that many consumers find it difficult to evaluate the complex products on offer. However, conflicts of interest, which are pervasive in some parts of the industry, can turn advice into a curse rather than a blessing for consumers, especially when consumers are not sufficiently wary. Through a simple model of financial advice, we overview the pros and cons of various policy interventions, such as imposing mandatory disclosure, banning commissions, and regulating contract cancellation terms.

The recent financial crisis has generated many distinct perspectives from various quarters. In this article, I review a diverse set of twenty-one books on the crisis, eleven written by academics, and ten written by journalists and one former Treasury Secretary. No single narrative emerges from this broad and often contradictory collection of interpretations, but the sheer variety of conclusions is informative, and underscores the desperate need for the economics profession to establish a single set of facts from which more accurate inferences and narratives can be constructed.

The response of aggregate labor supply to various changes in the economic environment is central to many economic issues, especially the optimal design of tax policies. Conventional wisdom based on studies in the 1980s and 1990s has long held that the analysis of micro data leads one to conclude that aggregate labor supply elasticities are quite small. In this paper we argue that this conventional wisdom does not hold up to empirically reasonable and relevant extensions of simple life cycle models that served as the basis for these conclusions. In particular, we show that several pieces of conventional wisdom fail in the presence of human capital accumulation or labor supply decisions that allow for adjustment along both the extensive and intensive margin. We conclude that previous estimates of small labor supply elasticities based on micro data are fully consistent with large aggregate labor supply elasticities.

This paper provides an overview of the analysis of the term structure of interest rates with a special emphasis on recent developments at the intersection of macroeconomics and finance. The topic is important to investors and also to policymakers, who wish to extract macroeconomic expectations from longer-term interest rates, and take actions to influence those rates. The simplest model of the term structure is the expectations hypothesis, which posits that long-term interest rates are expectations of future average short-term rates. In this paper, we show that many features of the configuration of interest rates are puzzling from the perspective of the expectations hypothesis. We review models that explain these anomalies using time-varying risk premia. Although the quest for the fundamental macroeconomic explanations of these risk premia is ongoing, inflation uncertainty seems to play a large role. Finally, while modern finance theory prices bonds and other assets in a single unified framework, we also consider an earlier approach based on segmented markets. Market segmentation seems important to understand the term structure of interest rates during the recent financial crisis.