R&D, patents and stock return volatility

Recent finance literature highlights the role of technological change in increasing firm specific (idiosyncratic) and aggregate stock return volatility, yet innovation data is not used in these analyses, leaving the direct relationship between innovation and stock return volatility untested. The paper investigates the relationship between volatility and innovation using firm level patent data. The analysis builds on the empirical work by Mazzucato (Rev Econ Dyn 5:318–345, 2002; J Evol Econ 13(5):491–512, 2003) where it is found that stock return volatility is highest during periods in the industry life-cycle when innovation is the most ‘radical’. In this paper we ask whether firms which invest more in innovation (more R&D and more patents) and/or which have more important innovations (patents with more citations) experience more volatility in their returns. Given that returns should in theory be higher, on average, for higher risk stocks, we also look at the effect of innovation on the level of returns. To take into account the competition between firms within industries, firm returns and volatility are measured relative to the industry average. We focus the analysis on firms in the pharmaceutical industry between 1974 and 1999. Results suggest that there is a positive and significant relationship between volatility, R&D intensity and the various patent related measures—especially when the innovation measures are filtered to distinguish the very innovative firms from the less innovate ones.     

Inferior factor in Cournot oligopoly revisited

We reconsider the recent work by Okuguchi (J Econ 101:125–131, 2010) on (possibly asymmetric) Cournotian firms with two production factors, one being inferior for each firm. It is shown there that an increase in the price of the inferior factor does raise the equilibrium industry output. In addition of providing a simpler and more rigorous proof of that result, we generalize it to the case of technologies with $s\ge 2$ factors and also allow some firms not to use the inferior one.     

Bargaining over productivity and wages when technical change is induced: implications for growth, distribution, and employment

I study a model of growth and income distribution in which workers and firms bargain à la Nash (Econometrica 18(2):155–162, 1950) over wages and productivity gains, taking into account the trade-offs faced by firms in choosing factor-augmenting technologies. The aggregate environment resulting from self-interested, objective function-maximizing decision rules on wages, productivity gains, savings and investment, is described by a two-dimensional dynamical system in the employment rate and output/capital ratio. The economy converges cyclically to a long-run equilibrium involving a Harrod-neutral profile of technical change, a constant rate of employment of labor, and constant input shares. The type of oscillations predicted by the model is qualitatively consistent with the available data on the United States (1963–2003), replicates the dynamics found in earlier models of growth cycles such as Goodwin (A growth cycle, in C.H. Feinstein (ed). Socialism, Capitalism and Economic Growth. Cambridge University Press, Cambridge 1967. Cambridge University Press, Cambridge, 1967); Shah and Desai (Econ J 91:1006–1010, 1981); van der Ploeg (J Macroecon 9:1–12, 1987); Flaschel (J Econ: Zeitschrift für Nationalökonomie 44:63–69, 1984) and Sportelli (J Econ: Zeitschrift für Nationalökonomie 61(1):35–64, 1995), and can be verified numerically in simulations. Institutional change, as captured by variations in workers’ bargaining power, has a positive effect on the long-run rate of growth of output per worker but a negative effect on long-run employment. Economic policy can also affect the growth and distribution pattern through changes in the unemployment compensation, which also have a positive long-run impact on labor productivity growth but a negative long-run impact on employment. In both cases, employment can overshoot its new equilibrium value along the transitional dynamics.     

Endogenous population with human and physical capital accumulation

This paper proposes an economic growth model with population growth and physical and human capital accumulation. The physical capital accumulation is built on the Solow growth model (Solow in Q J Econ 70:65–94, 1956). The education and human capital accumulation is influenced by the Uzawa–Lucas model (Uzawa in Int Econ Rev 6:18–31, 1965; Lucas in J Monet Econ 22:3–42, 1988). The population dynamics are influenced by the Haavelmo population model (Haavelmo in a study in the theory of economic evolution. Haavelmo, Amsterdam, 1954) and the Barro–Becker fertility choice model (Barro and Becker in Econometrica 57:481–501, 1989). We synthesize these dynamic forces in a compact framework, applying an alternative utility function proposed by Zhang (Econ Lett 42:105–110, 1993). The model describes a dynamic interdependence between population change, wealth accumulation, human capital accumulation, and division of labor. We simulate the model to demonstrate the existence of equilibrium points and to plot the motion of the dynamic system. We also examine the effects of changes in the propensity to have children, the mortality rate parameter, the propensity to receive education, the human capital utilization efficiency, and the mortality rate elasticity of human capital upon dynamic paths of the system.     

Definitions of ambiguous events and the smooth ambiguity model

We examine a variety of preference-based definitions of ambiguous events in the context of the smooth ambiguity model. We first consider the definition proposed in Klibanoff et?al. (Econometrica 73(6):1849?C1892, 2005) based on the classic Ellsberg two-urn paradox (Ellsberg Q J Econ 75:643?C669, 1961) and show that it satisfies several desirable properties. We then compare this definition with those of Nehring (Math Soc Sci 38(2):197?C213, 1999), Epstein and Zhang (Econometrica 69:265?C306, 2001), Zhang (Econ Theory 20:159?C181, 2002), and Ghirardato and Marinacci (J Econ Theory 102:251?C289, 2002). Within the smooth ambiguity model, we show that Ghirardato and Marinacci (J Econ Theory 102:251?C289, 2002) would identify the same set of ambiguous and unambiguous events as our definition while Epstein and Zhang (Econometrica 69:265?C306, 2001) and Zhang (Econ Theory 20:159?C181, 2002) would yield a different classification. Moreover, we discuss and formally identify two key sources of the differences compared to Epstein and Zhang (Econometrica 69:265?C306, 2001) and Zhang (Econ Theory 20:159?C181, 2002). The more interesting source is that these two definitions can confound non-constant ambiguity attitude and the ambiguity of an event.     

Information revelation in competitive markets

This paper analyzes a market with multiple sellers and horizontally differentiated products. We investigate the sellers’ incentives to reveal product relevant information that affects the buyer’s private valuation. The main finding is that if the number of sellers is sufficiently large, there is a unique symmetric equilibrium with full information disclosure. Thus, unlike the results by Lewis and Sappington (Int Econ Rev 35:309–327, 1994) and Johnson and Myatt (Am Econ Rev 93:756–784, 2006) for monopoly, which state that the monopolist reveals either full information or no information, intense competition results in a single extreme with respect to information disclosure. We show that the market is always inefficient, but the magnitude of inefficiency converges to zero at a high rate as competition intensifies.     

Are the treasures of game theory ambiguous?

Goeree and Holt (Am Econ Rev 91:1402?C1422, 2001) experimentally study a number of games. In each case, they initially find strong support for Nash equilibrium; however, by changing an apparently irrelevant parameter, they find results which contradict Nash equilibrium. In this paper, we study the five normal form games from Goeree and Holt (Am Econ Rev 91:1402?C1422, 2001). We argue that their results may be explained by the hypothesis that subjects view their opponents?? behaviour as ambiguous. Ambiguity-aversion causes players to avoid strategies, which give low out of equilibrium payoffs. Similarly, ambiguity preference can make strategies with high payoffs more attractive.     

A note on the robustness of Card and Krueger (1994) and Neumark and Wascher (2000)

This note adds to the discussion originating from Card and Krueger (Am Econ Rev 84:772–793, 1994) and Neumark and Wascher (Am Econ Rev 90:1362–1396, 2000) by re-evaluating their results using the semiparametric difference-in-differences estimator introduced in Abadie (Rev Econ Stud 72:1–19, 2005). The note addresses the question of whether the differences in the original datasets can explain the differences in their conclusions. Although we observe heterogenous employment effects together with the differences in the distributions, the results show that the original findings on the overall employment effect of a minimum wage are fairly robust and just slightly changed when the differences in the distributions of the observed covariates are taken into account.     

The effects of the take-option in dictator-game experiments: a comment on Engel’s (2011) meta-study

In this paper, we report a replication of Engel’s (Exp. Econ. 14(4):583–610, 2011) meta-study of dictator game experiments. We find Engel’s meta-study of dictator game experiments to be robust, with one important exception: the coding of the take-option (List in J. Polit. Econ. 115(3):482–493, 2007; Bardsley in Exp. Econ. 11(2):122–133, 2008; Cappelen et al. in Econ. Lett. 118(2):280–283, 2013). While Engel reports this as having no statistically significant effect, in our replications, we find an economically and statistically significant negative effect on giving in line with the relevant literature.     

A competitive equilibrium for a warm-glow economy

The warm-glow model (Andreoni in J Political Econ 97:1447–1458, 1989; Econ J 100:464–477, 1990) of public goods provision has received widespread interest, yet surprisingly most attention has focused on the voluntary contribution equilibrium of the model, and only very little attention has been devoted to the competitive equilibrium. In this paper, we introduce the concept of competitive equilibrium for a warm-glow economy (henceforth, warm-glow equilibrium) and establish both existence and welfare properties. The warm-glow equilibrium concept may prove to be very useful to the normative and positive theory of public goods provision. First, it is a price-based mechanism achieving efficient outcomes. Second, not only could the warm-glow equilibria outcomes serve as a point of reference to measure free-riding and welfare loss but also, as suggested by Bernheim and Rangel (Behavioral Economics and Its Applications, 2007), in large economies they may be approximated by Walrasian equilibria outcomes.     

Cobb-Douglas preferences under uncertainty

This paper axiomatizes Cobb-Douglas preferences under uncertainty. First, we extend the original Trockel (Econ Lett 30:7–10, 1989)’s axiomatic foundation to a general state space framework based on the Strong Homotheticity Axiom, obtaining also the incomplete case a la Bewley (Decis Econ Financ 25:79–110, 2002). We show that this key axiom for the Cobb-Douglas expected utility specification is refuted by Ellsberg’s uncertainty aversion behavioral pattern. Our main result provides a set of meaningful axioms characterizing Cobb-Douglas min-expected utility preferences, an important class of uncertainty averse preferences for studying the consequences of ambiguity in finance and other fields. Finally, we present briefly how to obtain more general representations like the variational case.     

Pluralism(s) in economics: lessons from complexity and innovation. A review paper

My analysis focuses on two main observations. First, many competing schools of thoughts are currently present in economics with no predominant paradigm. We are experiencing an era of pluralism (Davis J Econ Methodol 14(3):275–290, 2007, Camb J Econ 32:249–366, 2008; Colander 2000; Colander et al. J Polit Econ 16(4):485–499, 2004). The term ‘pluralism’ is extremely interesting since, as I will show, it has different dimensions to it. These offer insights into interpreting the tangled universe of the economics. Second, there is a progressive intertwining of innovation economics with complexity economics, which I argue provides an instance of the above-described shift toward pluralism.     

Trembles in extensive games with ambiguity averse players

We introduce and analyze three definitions of equilibrium for finite extensive games with imperfect information and ambiguity averse players. In a setting where players’ preferences are represented by maxmin expected utility, as characterized in Gilboa and Schmeidler (J Math Econ 18(2):141–153, 1989), our definitions capture the intuition that players may consider the possibility of slight arbitrary mistakes. This generalizes the idea leading to trembling-hand perfect equilibrium as introduced in Selten (Int J Game Theory 4(1):25–55, 1975), by allowing for ambiguous trembles characterized by sets of distributions. We prove existence for two of our equilibrium notions and relate our definitions to standard equilibrium concepts with expected utility maximizing players. Our analysis shows that ambiguity aversion can lead to behavioral implications that are distinct from those attained under expected utility maximization, even if ambiguous beliefs only arise from the possibility of slight mistakes in the implementation of unambiguous strategies.     

On a closed-form solution to the stochastic Lucas–Uzawa model

Bucci et al. (J Econ 103:83–99, 2011) argue that under two parametric restrictions, there exists a closed-form solution path to the two-sector endogenous growth model of Lucas–Uzawa. However, they assume that the value function is a function of both the current and the initial values of the state variables. As Wälde (J Econ Dyn Control 35:616–622, 2011a) argues, the value function should depend only on the current state variables when the technology follows a geometric Brownian motion. I follow Wälde (J Econ Dyn Control 35:616–622, 2011a) and obtain, under some inequality constraints, a different value function.     

Kaldorian assumptions and endogenous fluctuations: a note on Schinasi’s IS–LM model

Results on Schinasi’s (Rev Econ Stud 48:649–653, 1981; J Econ Theory 28:369–375, 1982) variant of the dynamic fixed-price IS–LM model have remained so far confined to Kaldorian type economies, namely to those economies which present a greater-than-unity marginal propensity to spend out of income. This paper shows that, in the case of a negative interest rate sensitivity of savings, stable endogenous cycles can actually emerge as equilibrium solutions of the model also in the case of non-Kaldorian type economies.     

More equal but not so fair: an analysis of Brazilian income distribution from 1995 to 2009

This study measures unfair inequality in Brazil between 1995 and 2009. To achieve that, we used the statistical tool developed by Almås et al. (J Public Econ 95:488–499, 2011) and the concept of “responsibility-sensitive” fairness proposed by Bossert (Math Soc Sci 29:1–17, 1995), Konow (J Econ Behav Organ 31(1):13–35, 1996) and Cappelen and Tungodden (Fairness and the proportionality principle, Discussion paper SAM 31/2007. Norwegian School of Economics and Business Administration, 2007). The results indicate that the fairness level in Brazil remained unchanged throughout the analyzed period.     

A note on mergers and relocation

Posada and Straume (J Econ 83:243?C265, 2004) analyze a three-firm model of a circular city where two of the firms merge and may choose to relocate. They propose an equilibrium with relocation where taking part in the merger yields higher profits than staying outside, i.e., relocation may solve the so-called merger paradox. In this note, it is shown that the equilibrium candidate considered is not an equilibrium.     

Fictitious students creation incentives in school choice problems

We identify a new channel through which schools can potentially manipulate the well-known student and school-optimal stable mechanisms. We introduce two fictitious students creation manipulation notions where one of them is stronger. While the student and school-optimal stable mechanisms turn out to be weakly fictitious student-proof under acyclic (Ergin in Econometrica 88:485–494, 2002) and essentially homogeneous (Kojima in Games Econ Behav 82:1–14, 2013) priority structures, respectively, they still lack strong fictitious student-proofness. We then compare the mechanisms in terms of their vulnerability to manipulations in the sense of Pathak and Sönmez (Am Econ Rev 103(1):80–106, 2013) and find out that the student-optimal stable mechanism is more manipulable than the school-optimal one. Lastly, in the large market setting of Kojima and Pathak (Am Econ Rev 99(3):608–627, 2009), the student-optimal stable mechanism becomes weakly fictitious student-proof as the market is getting large.     

Monopoly pricing when consumers are antagonized by unexpected price increases: a “cover version” of the Heidhues–K?szegi–Rabin model

This paper reformulates and simplifies a recent model by Heidhues and K?szegi (The impact of consumer loss aversion on pricing, Mimeo, 2005), which in turn is based on a behavioral model due to K?szegi and Rabin (Q J Econ 121:1133?C1166, 2006). The model analyzes optimal pricing when consumers are loss averse in the sense that an unexpected price hike lowers their willingness to pay. The main message of the Heidhues?CK?szegi model, namely that this form of consumer loss aversion leads to rigid price responses to cost fluctuations, carries over. I demonstrate the usefulness of this ??cover version?? of the Heidhues?CK?szegi-Rabin model by obtaining new results: (1) loss aversion lowers expected prices; (2) the firm??s incentive to adopt a rigid pricing strategy is stronger when fluctuations are in demand rather than in costs.     

Optimality of impulse harvesting policies

We explore the link between cyclical and smooth resource exploitation. We define an impulse control framework which can generate both cyclical solutions and steady-state solutions. Our model can admit convex and concave profit functions and allows the integration of different stock-dependent profit functions. We show that the strict concavity of the profit function is only a special case of a more general condition, related to submodularity, that ensures the existence of optimal cyclical policies. We then establish a link with the discrete-time models with cyclical solutions by Benhabib and Nishimura (J Econ Theory 35:284–306, 1985) and Dawid and Kopel (J Econ Theory 76:272–297, 1997). For the steady-state solution, we explore the relation to Clark’s (1976) continuous control model.