No‐arbitrage implies power‐law market impact and rough volatility

Market impact is the link between the volume of a (large) order and the price move during and after the execution of this order. We show that in a quite general framework, under no‐arbitrage assumption, the market impact function can only be of power‐law type. Furthermore, we prove this implies that the macroscopic price is diffusive with rough volatility, with a one‐to‐one correspondence between the exponent of the impact function and the Hurst parameter of the volatility. Hence, we simply explain the universal rough behavior of the volatility as a consequence of the no‐arbitrage property. From a mathematical viewpoint, our study relies, in particular, on new results about hyper‐rough stochastic Volterra equations.     

Measuring competition in spatial retail

We propose and estimate a spatially aggregated discrete-choice model with overlapping consumer choice sets and demographic-driven heterogeneity that varies by chain. Our approach avoids the need to define markets ex ante and captures rich substitution patterns, even in the absence of price data. An application to the US grocery industry illustrates the importance of location, format, and the spatial distribution of consumers in shaping the competitive environment. Contrary to conventional wisdom, we find substantial cross-format competition between supercenters, clubs, and traditional grocers. Finally, we evaluate two representative mergers between supermarket chains to demonstrate how our estimates inform antitrust policy.     

Is There a Causal Effect of Working Part‐Time on Current and Future Wages?

In this paper, I study the causal effects of part‐time work on current and future wages. To estimate these effects, I use a random effects model with a wage equation capturing the employment history and a dynamic multinomial probit component for the choice of employment status. Exclusion restrictions from the institutional context are exploited to support identification. The results suggest that working part‐time with few hours has a large causal effect on current wages, but more extensive part‐time work does not reduce current wages. However, both types of part‐time work lead to negative long‐term wage effects.     

Two-stage DEA: <Emphasis Type="Italic">caveat emptor</Emphasis>

This paper examines the wide-spread practice where data envelopment analysis (DEA) efficiency estimates are regressed on some environmental variables in a second-stage analysis. In the literature, only two statistical models have been proposed in which second-stage regressions are well-defined and meaningful. In the model considered by Simar and Wilson (J Prod Anal 13:49–78, 2007), truncated regression provides consistent estimation in the second stage, where as in the model proposed by Banker and Natarajan (Oper Res 56: 48–58, 2008a), ordinary least squares (OLS) provides consistent estimation. This paper examines, compares, and contrasts the very different assumptions underlying these two models, and makes clear that second-stage OLS estimation is consistent only under very peculiar and unusual assumptions on the data-generating process that limit its applicability. In addition, we show that in either case, bootstrap methods provide the only feasible means for inference in the second stage. We also comment on ad hoc specifications of second-stage regression equations that ignore the part of the data-generating process that yields data used to obtain the initial DEA estimates.     

Exploring the structure and meaning of public service motivation in the Turkish public sector: a test of the mediating effects of job characteristics

Using a data set consisting of 315 middle-managers at the district level in the Turkish public sector, we develop a structural equation model (SEM) for assessing the impact of empowerment and stewardship on public service motivation (PSM) through job characteristics. The results demonstrate that stewardship and empowerment are distinct ‘levers’ that managers can use in novel ways to influence PSM; and cultural context may factor into the manipulation of these levers. We find that job-based mediators may not compliment leadership styles and self-generating rewards, but, rather work separately in their appeal to PSM.     

From a System of National Accounts to a Process of National Wellbeing Accounting

There are repeated calls to go ‘Beyond GDP’, for measures of wellbeing and progress in addition to those that the System of National Accounts (SNA) is designed to provide. We identify key issues that can help build on the rigour of SNA whilst fitting the measurement of economic performance within a broader assessment of national wellbeing and progress. Such drivers are already leading to a proliferation of indicators and accounts, for example in the development of non‐monetary measures of natural resources, but there are significant measurement challenges, not least the question of whether a single, overall measure or index of wellbeing is valid. But the challenge of measurement, per se, is one thing: in our view, a more critical issue is whether the measures will actually be used. We propose a dynamic and multi‐staged approach for developing SNA, embracing the production and use of measures. This would start by identifying user requirements for wider measures, to provide the basis for national and cross‐national developments in well‐being accounting. We envisage greater branding and marketing of national well‐being concepts to promote measures and support their use. We call for outreach by producers, so that there is dialogue about the development and use of measures.     

The post‐application labour market consequences of employment tribunal claims

This article examines the post‐application employment consequences for individuals registering complaints to Employment Tribunals following dismissal or redundancy. We consider several pieces of evidence: (a) the probability of finding another job, (b) the time taken to get a new job and (c) the pay/status of the new job. Our results indicate that age plays a significant role in aspects (a) and (c), while those who previously held managerial positions generally took longest to get a new job and found it most difficult to achieve a similar level of pay/status in their current jobs. Long‐term health problems/disability is associated with significantly worse outcomes on all three measures. Respondents whose cases were dismissed by tribunals without hearings fared worst in terms of obtaining a new job and the time it took to do so. There are, however, fewer differences by tribunal outcome in the relative pay/status of the claimant's current job.