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on Efficiency and Productivity |
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Issue of 2018‒06‒25
nineteen papers chosen by |
| By: | Andrea Garnero; François Rycx; Isabelle Terraz |
| Abstract: | How do firm-level collective agreements affect firm performance in a multi-level bargaining system? Using detailed Belgian linked employer-employee panel data, our findings show that firm agreements increase both wage costs and productivity (with respect to sector-level agreements). Relying on a recent approach developed by Bartolucci (2014), they also indicate that firm agreements exert a stronger impact on wages than on productivity, so that profitability is hampered. However, this rent-sharing effect only holds in manufacturing. In private sector services, the raw wage premium associated to firm agreements is entirely driven by compositional effects. Furthermore, estimates show that firm agreements lead to significantly more rent-sharing among firms operating in less competitive environments. Firm agreements are thus mainly found to raise wages beyond productivity when the rents to be shared between workers and firms are relatively big. Overall, this suggests that firm-level agreements benefit to both employers and employees – through higher productivity and wages – without being very detrimental to firms’ performance. |
| Keywords: | Collective bargaining; productivity; labour costs; linked panel data |
| JEL: | C33 J24 J31 |
| Date: | 2018–06–04 |
| URL: | http://d.repec.org/n?u=RePEc:sol:wpaper:2013/271425&r=eff |
| By: | Stephan Kyburz, Huong Quynh Nguyen |
| Abstract: | Inward foreign direct investment (FDI) is regarded as a key engine of industrial growth and technological progress, especially in emerging markets. Regarding the relevance of geographic proximity between foreign and domestic firms for FDI spillover effects, there is yet little clear evidence, owing to a lack of precise location specific firm-level data. This paper presents the so far spatially most detailed analysis of FDI spillover effects by geo-referencing the census of Vietnamese enterprises for the period 2005 to 2010, allowing us to measure the changing presence of foreign invested firms around each domestic firm. We apply a first-differenced two-stageleast- squares estimator to identify spillover effects from proximate FDI exposure on TFP growth of domestic manufacturing firms. We find positive and significant within-industry (horizontal) spillover effects within radii of 2 to 10 km, that decay beyond. Importantly, in particular small and medium enterprises (SMEs) gain from foreign firms in their vicinity. Furthermore, vertical spillovers through forward and backward linkages to other manufacturing firms are localized, while vertical spillovers from foreign firms in the service sector are less geographically restricted. |
| Keywords: | foreign direct investment, spillover effects, geographic proximity, horizontal and vertical linkages |
| JEL: | D22 D24 F23 O12 O14 O33 R11 R32 |
| Date: | 2017–10 |
| URL: | http://d.repec.org/n?u=RePEc:rdv:wpaper:credresearchpaper16&r=eff |
| By: | Uwe Cantner (FSU Jena); Holger Graf (FSU Jena); Ekaterina Prytkova (FSU Jena); Simone Vannuccini (FSU Jena) |
| Abstract: | A growing number of studies identify a generalized slowdown in labor productivity growth. The very existence of the slowdown ignited a series of academic debates suggesting that secular stagnation or 'mismeasurement' problems are at the root of the observed trends. We posit that the composition of aggregate productivity matters. In a nutshell, we make the analysis of productivity growth slowdown more fine-grained by shifting the focus to the industry level, considering that the downward trend identified at the macroeconomic level emerges from the aggregation of diverse industry-level productivity trends. We perform an analysis of the structural dynamics of labor productivity by conducting a non-parametric dynamic decomposition exercise that separates within (improvement) and between (structural change) effects for 10 OECD countries. By pooling industries in groups identified according to two different taxonomies - one related to R&D intensities rankings, and the other built upon the Pavitt taxonomy of sources of technological change -, this study assess the industry-level contributions to the slowdown and the trends over time of the within and between components. We interpret our findings highlighting common patterns and suggest two related technological explanations for the productivity slowdown: one based on a Baumol-disease-like effect driven by structural change and another based on implementation lags and/or on an exhaustion of technological opportunities - that is, on decreasing returns in innovative activities. To investigate that, we complement our productivity analysis with evidence on innovation slowdown trends, looking at aggregate and compositional trends. We explore the innovation slowdown using an array of indicators based on the notion of 'idea- TFP' and show that there is a generalized evidence for its occurrence. Eventually, we relate productivity and innovation slowdowns deriving tables of trends co-movements, weighted by input-output matrices coefficients, and clustered by Pavitt industry group. We interpret these relationships and highlight patterns and clusters of significant correlations. |
| Keywords: | productivity slowdown, decomposition, industrial dynamics, innovation |
| JEL: | L16 O30 O47 |
| Date: | 2018–06–18 |
| URL: | http://d.repec.org/n?u=RePEc:jrp:jrpwrp:2018-006&r=eff |
| By: | Richard Kališ (University of Economics Bratislava) |
| Abstract: | In this study, technical efficiency of Slovak general hospitals was investigated. The well-known non-parametric Data Envelopment Analysis was used to compare performance of Slovak health care providers. Results are based on four slightly differentiated models. Both CRS and VRS variation with different input approaches were used. Our results suggest low average efficiency in Slovak hospitals in the range 0.45 to 0.62 with great variations in efficiency score between individual Decision Making Units (DMUs). These results are relative without appropriate cross-country comparisons. Furthermore, in type of hospital entity there is no significant difference in efficiency score. However there is not a single efficient DMU in a group of municipality hospitals. Although, these results must be taken with caution due to questionable quality of data, this paper provides some valuable overview on technical efficiency of health care providers |
| Keywords: | data envelopment analysis; hospitals; efficiency |
| JEL: | P41 G34 C44 |
| Date: | 2018–10–06 |
| URL: | http://d.repec.org/n?u=RePEc:brt:depwps:012&r=eff |
| By: | Carlo Altomonte; Domenico Favoino; Tommaso Sonno |
| Abstract: | We extend a framework of monopolistically competitive firms heterogeneous in productivity and with endogenous markups (as in Melitz and Ottaviano, 2008) to incorporate the presence of financial frictions. Before producing, firms need to obtain a loan necessary to cover part of production costs, for which they have to pledge collateral in the form of tangible assets. In addition to productivity, firms are also heterogeneous in their financial capability: some firms have access to collateral at lower costs. As a result, financial capability and collateral requirements enter together with productivity in the expression of the equilibrium firm-level markup. At the aggregate level, the model shows that tighter credit constraints in the form of higher collateral requirements mitigate the pro-competitive effect of trade. We validate our theoretical results capitalizing on a representative sample of manufacturing firms surveyed across a subset of European countries during the financial crisis. Guided by theory, we estimate for each firm financial capability, TFP and markups. We then employ those estimates to structurally retrieve from the model a firm-specific measure of collateral requirements (a proxy of credit constraint), and test our main propositions. |
| Keywords: | Credit constraints, heterogeneous rms, markups, international trade |
| JEL: | F10 F14 G32 |
| URL: | http://d.repec.org/n?u=RePEc:baf:cbafwp:cbafwp1755&r=eff |
| By: | Grinza, Elena (University of Milan); Rycx, Francois (Free University of Brussels) |
| Abstract: | We investigate the impact of sickness absenteeism on productivity by using rich longitudinal matched employer-employee data on Belgian private firms. We deal with endogeneity, which arises from unobserved firm heterogeneity and reverse causality, by applying a modified version of the Ackerberg et al's (2015) control function method, which explicitly removes firm fixed effects. Our main finding is that, in general, sickness absenteeism substantially dampens firm productivity. An increase of 1 percentage point in the rate of sickness absenteeism entails a productivity loss of 0.24%. Yet, we find that the impact is much diversified depending on the categories of workers who are absent and across different types of firms. Our results show that sickness absenteeism is detrimental mainly when absent workers are high-tenure or blue-collar workers. Moreover, they show that sickness absenteeism is harmful mostly to industrial firms, high capital-intensive companies, and small- and medium-sized enterprises. This overall picture is coherent with the idea that sickness absenteeism is problematic when absent workers embed high levels of firm/task-specific (tacit) knowledge, when the work of absent employees is highly interconnected with the work of other employees (e.g., along the assembly line), and when firms face more limitations in substituting temporarily absent workers. |
| Keywords: | sickness absenteeism, firm productivity, semiparametric methods for estimating production functions, longitudinal matched employer-employee data |
| JEL: | D24 M59 I15 |
| Date: | 2018–05 |
| URL: | http://d.repec.org/n?u=RePEc:iza:izadps:dp11543&r=eff |
| By: | Fabiano Schivardi; Tom Schmitz |
| Abstract: | Since the middle of the 1990s, productivity growth in Southern Europe has been substantially lower than in other developed countries. In this paper, we argue that this divergence was partly caused by inefficient management practices, which limited Southern Europe's gains from the IT Revolution. To quantify this effect, we build a multi-country general equilibrium model with heterogeneous firms and workers. In our model, the IT Revolution generates divergence for three reasons. First, inefficient management limits Southern firms' productivity gains from IT adoption. Second, IT increases the aggregate importance of management, making its inefficiencies more salient. Third, IT-driven wage increases in other countries stimulate Southern high-skill emigration. We calibrate our model using firm-level evidence, and show that it can account for 28% of Italy's, 39% of Spain's and 67% of Portugal's productivity divergence with respect to Germany between 1995 to 2008. Keywords: TFP, Southern Europe, Divergence, IT Technology adoption, Management. JEL Codes: L23, O33 |
| Date: | 2018 |
| URL: | http://d.repec.org/n?u=RePEc:igi:igierp:624&r=eff |
| By: | Brian Lucking; Nicholas Bloom; John Van Reenen |
| Abstract: | This paper revisits the results of Bloom, Schankerman, and Van Reenen (2013) examining the impact of R&D on the performance of US firms, especially through spillovers. We extend their analysis to include an additional 15 years of data through 2015, and update the measures of firms' interactions in technology space and product market space. We show that the magnitude of R&D spillovers appears to have been broadly similar in the second decade of the 21st Century as it was in the mid-1980s. However, there does seem to have been some increase in the wedge between marginal social returns to R&D and marginal private returns with the ratio of marginal social to private returns increasing to a factor of 4 from 3. There is certainly no evidence that the divergence between public and private return has narrowed. Positive spillovers appeared to increase in the 1995-2004 boom. |
| JEL: | E22 |
| Date: | 2018–05 |
| URL: | http://d.repec.org/n?u=RePEc:nbr:nberwo:24622&r=eff |
| By: | François-Seck Fall (LEREPS - Laboratoire d'Etude et de Recherche sur l'Economie, les Politiques et les Systèmes Sociaux - UT1 - Université Toulouse 1 Capitole - UT2 - Université Toulouse 2 - Institut d'Études Politiques [IEP] - Toulouse - ENSFEA - École Nationale Supérieure de Formation de l'Enseignement Agricole de Toulouse-Auzeville); Akim Al-Mouksit (UCAD - Université Cheikh Anta Diop , UMR DIAL - Université Paris Dauphine (Paris 9)); Harouna Wassongma (UCAD - Université Cheikh Anta Diop) |
| Abstract: | Microfinance has played a key role in the fight against exclusion and the promotion of entrepreneurship in developing countries. An important question today is how to increase the reach and profitability of microfinance, in a context where subsidies are withdrawing to promote the viability and sustainability of microfinance institutions (MFIs). Efficiency analysis has found favor in this context and has attracted growing interest among professionals, partners, and researchers. Abundant empirical work has been conducted over the last ten years on this subject, in very different contexts and with different methodologies. The purpose of this article is to provide a meta-regression analysis on parametric and nonparametric estimations of Mean Technical Efficiency (MTE) in microfinance, using a data set of 262 observations from 38 studies. The results show that, in the microfinance industry, MTE scores have increased over time. However, with an MTE rate of approximately 61.1%, there is room for improving efficiency. MFIs use more resources than necessary for the results achieved in terms of outreach and revenue generated. Our results show heterogeneity of MTE according to the methodological approach of the studies. Studies with a larger number of variables (inputs and outputs) produced higher MTE scores than did those with a smaller number of variables. Studies using the variable returns to scale assumption resulted in higher MTE scores than those using constant returns to scale. In addition, those with a production approach had higher MTEs than did those using the intermediation approach, while studies of a large number of MFIs had lower scores than did those involving a small sample size. Moreover, research estimating social efficiency generated lower MTEs compared to those estimating financial efficiency. Studies using data from African MFIs obtained lower MTEs than did those on MFIs in Latin America and MENA, which confirms the poor performance of African microfinance. |
| Keywords: | SFA,Meta-analysis,Microfinance,Technical efficiency,DEA |
| Date: | 2018–07 |
| URL: | http://d.repec.org/n?u=RePEc:hal:journl:hal-01794625&r=eff |
| By: | Daniele Tori (Open University); Özlem Onaran |
| Abstract: | In this paper we estimate the effects of financialization on physical investment in selected western European countries using panel data based on the balance-sheets of publicly listed non-financial companies (NFCs) supplied by Worldscope for the period 1995-2015. We find robust evidence of an adverse effect of both financial payments (interests and dividends) and financial incomes on investment in fixed assets by the NFCs. This finding is robust for both the pool of all Western European firms and single country estimations. The negative impacts of financial incomes are non-linear with respect to the companies' size: financial incomes crowd-out investment in large companies, and have a positive effect on the investment of only small, relatively more credit-constrained companies. Furthermore, we find that a higher degree of financial development is associated with a stronger negative effect of financial incomes on companies' investment. This finding challenges the common wisdom on 'finance-growth nexus'. Our findings support the 'financialization thesis' that the increasing orientation of the non-financial sector towards financial activities is ultimately leading to lower physical investment, hence to stagnant or fragile growth, as well as long term stagnation in productivity. |
| Keywords: | financialization, financial development, firm-level data, Europe |
| JEL: | C23 D22 G31 |
| Date: | 2017–06 |
| URL: | http://d.repec.org/n?u=RePEc:pke:wpaper:1705&r=eff |
| By: | Badunenko, Oleg; Tauchmann, Harald |
| Abstract: | When analyzing what determines the efficiency of production, regressing efficiency scores estimated by DEA on explanatory variables has much intuitive appeal. Simar and Wilson (2007) show that this naïve two-stage estimation procedure suffers from severe flaws, that render its results, and in particular statistical inference based on them, questionable. At the same time they propose a statistically grounded bootstrap based two-stage estimator that eliminates the above mentioned weaknesses of its naïve predecessors and comes in two variants. This article introduces the new Stata command simarwilson that implements either variant of the suggested estimator in Stata. The command allows for various options, and extends the original procedure in some respects. For instance, it allows for analyzing both, output- and input-oriented efficiency. To demonstrate the capabilities of the new command simarwilson we use data from the Penn World Tables and the Global Competitiveness Report by the World Economic Forum to perform a cross-country empirical study about the importance of quality of governance of a country for its efficiency of output production. |
| Keywords: | DEA,two-stage estimation,truncated regression,bootstrap,efficiency,bias correction,environmental variables |
| Date: | 2018 |
| URL: | http://d.repec.org/n?u=RePEc:zbw:iwqwdp:082018&r=eff |
| By: | David Bartolini |
| Abstract: | Slow productivity growth in advanced economies holds back income gains and therefore improvements in well-being. Sluggish productivity gains in aggregate hide a growing gap between firms at the frontier, which display sustained productivity growth, and the rest of firms whose productivity stagnates. The empirical analysis – based on firm-level data for the period 1998–2014 – uncovers the existence of a tax burden gap alongside the productivity gap: firms at the frontier pay less for each dollar of profits than lagging firms. This heterogeneous impact of taxation may hinder productivity diffusion, as it reduces incentives (and opportunities) for lagging firms to catch up with the frontier. The negative impact of taxation is particularly important when associated with cash constraints, weak demand and other framework conditions (e.g. labour market legislation, trade openness). The analysis shows that complementing tax incentives with policies to ease cash constraints would help to narrow the productivity gap. |
| Keywords: | access to credit, effective business taxation, market regulation, Productivity |
| JEL: | D24 H25 |
| Date: | 2018–06–11 |
| URL: | http://d.repec.org/n?u=RePEc:oec:ecoaaa:1475-en&r=eff |
| By: | Arvid Raknerud; Diana-Cristina Iancu (Statistics Norway); Øivind A. Nilsen |
| Abstract: | We analyse all the major sources of direct and indirect R&D subsidies in Norway in the period 2002- 2013 and compare their effects on individual firms’ performance. Firms that received support are matched with a control group of firms that did not receive support using a combination of stratification and propensity score matching. Changes in performance indicators before and after support in the treatment group are compared with contemporaneous changes in the control group. We find that the average effects of R&D support among those who obtained grants and/or subsidies are positive and significant in terms of performance indicators related to economic growth: value added, sales revenue and number of employees. The estimated effects are larger for start-up firms than incumbent firms when the effects are measured as relative effects (in percentage points), but smaller when these effects are translated into level effects. Finally, we do not find positive effects on return to total assets or productivity for firms who received support compared with the control group. |
| Keywords: | Public policy; Firm performance; Treatment effects; Stratification; Propensity score matching; Productivity |
| JEL: | C33 C52 D24 O38 |
| Date: | 2018–06 |
| URL: | http://d.repec.org/n?u=RePEc:ssb:dispap:878&r=eff |
| By: | Lukas Ahnert; Pascal Vogt; Volker Vonhoff; Florian Weigert |
| Abstract: | This paper investigates the impact of stress testing results on bank's equity and CDS performance using a large sample of ten tests from the US CCAR and the European EBA regimes in the time period between 2010 and 2017. We find that passing banks experience positive abnormal equity returns and tighter CDS spreads, while failing banks show strong drops in equity prices and widening CDS spreads. Interestingly, we also document strong market reactions at the announcement date of the stress tests. A bank’s asset quality and its return on equity at the time of the announcement are significant predictors of the pass/fail outcome of a bank. |
| Keywords: | Banks, Stress Testing, Equity Performance, CDS Performance |
| JEL: | G00 G21 G28 |
| Date: | 2018–05 |
| URL: | http://d.repec.org/n?u=RePEc:usg:sfwpfi:2018:14&r=eff |
| By: | Nicholas Ryan |
| Abstract: | This paper studies a field experiment among energy-intensive Indian manufacturing plants that offered energy consulting to raise energy productivity, the amount plants can produce with each unit of energy. Treatment plants, after two years and relative to the control, run longer hours, demand more skilled labor and use 9.5 percent more electricity (standard error 7.3 percent). I assume that the treatment acted only through energy productivity to estimate the plant production function. The model estimates imply that energy complements skill and capital and that energy demand therefore responds more strongly to a productivity shock when plants can adjust these inputs. |
| JEL: | D24 O14 Q41 |
| Date: | 2018–05 |
| URL: | http://d.repec.org/n?u=RePEc:nbr:nberwo:24619&r=eff |
| By: | Richard Hornbeck; Enrico Moretti |
| Abstract: | We estimate the local and aggregate effects of total factor productivity growth on US workers' earnings, housing costs, and purchasing power. Drawing on four alternative instrumental variables, we consistently find that when a city experiences productivity gains in manufacturing, there are substantial local increases in employment and average earnings. For renters, increased earnings are largely offset by increased cost of living; for homeowners, the benefits are substantial. Strikingly, local productivity growth reduces local inequality, as it raises earnings of local less-skilled workers more than the earnings of local more-skilled workers. This is due, in part, to lower geographic mobility of less-skilled workers. However, local productivity growth also has important general equilibrium effects through worker mobility. We estimate that 38% of the overall increase in workers' purchasing power occurs outside cities directly affected by local TFP growth. The indirect effects on worker earnings are substantially greater for more-skilled workers, due to greater geographic mobility of more-skilled workers, which increases inequality in other cities. Neglecting these general equilibrium effects would both understate the overall magnitude of benefits from productivity growth and misstate their distributional consequences. Overall, US workers benefit substantially from productivity growth. Summing direct and indirect effects, we find that TFP growth from 1980 to 1990 increased purchasing power for the average US worker by 0.5-0.6% per year from 1980 to 2000. These gains do not depend on a worker's education; rather, the benefits from productivity growth mainly depend on where workers live. |
| JEL: | E24 J0 R0 |
| Date: | 2018–05 |
| URL: | http://d.repec.org/n?u=RePEc:nbr:nberwo:24661&r=eff |
| By: | Louisa Andriamasy (UEVE - Université d'Évry-Val-d'Essonne); Walter Briec (CRESEM - Centre de Recherche sur les Sociétés et Environnements en Méditerranées - UPVD - Université de Perpignan Via Domitia); Stéphane Mussard (LAMETA - Laboratoire Montpelliérain d'Économie Théorique et Appliquée - UM1 - Université Montpellier 1 - UM3 - Université Paul-Valéry - Montpellier 3 - Montpellier SupAgro - Centre international d'études supérieures en sciences agronomiques - INRA Montpellier - Institut national de la recherche agronomique [Montpellier] - UM - Université de Montpellier - CNRS - Centre National de la Recherche Scientifique - Montpellier SupAgro - Institut national d’études supérieures agronomiques de Montpellier, UNIMES - Université de Nîmes) |
| Abstract: | The purpose of this paper is to establish a topological relation between several known production models, precisely a link between -convex and Cobb–Douglas production models. The framework is based on the algebraic structures of the technology sets, issued from data envelopment, respecting either the assumption of constant elasticity of substitution and transformation (CES–CET) or -returns to scale. It is shown that the Painlevé–Kuratowski limit of the CES–CET technology provides either -convex or inverse -convex technologies. Also, -returns to scale models have topological limits relevant with constant return to scale -convex (or inverse -convex) technologies. |
| Keywords: | Non-parametric production models, Painlevé–Kuratowski limit, lattice, CES–CET model, generalized convexity, alpha-returns to scale |
| Date: | 2017–02–07 |
| URL: | http://d.repec.org/n?u=RePEc:hal:journl:hal-01781483&r=eff |
| By: | Timothy Neal (UNSW School of Economics); Michael Keane (UNSW School of Economics) |
| Abstract: | We investigate the impact of climate change on U.S. agricultural productivity using county-level yield and weather data from 1950 to 2015. We present two new methods of modelling how producers adapt agricultural techniques to harsh temperatures, including a new panel data estimator that allows for two-dimensional fixed-effects in slopes. We find evidence of adaptation to geographic and temporal variation in climate, but it has stalled since 1989. We show that adaptation implies fixed-effects slope heterogeneity in the relationship between crop yield and temperature, and ignoring this leads to biased estimates of temperature sensitivity. We use our estimates to project corn yields to 2100 using a variety of climate models and emission scenarios, and find that unmitigated climate change will have severe effects on yields. Our models indicate that adaptation techniques can mitigate 10 to 45% of the damage, but significant emissions reductions can mitigate far more (i.e., 42 to 91%). |
| JEL: | C23 C54 D24 Q15 Q51 Q54 Q55 |
| Date: | 2018–05 |
| URL: | http://d.repec.org/n?u=RePEc:swe:wpaper:2018-08&r=eff |
| By: | Astadi Pangarso (Faculty of Communication and Business, Telkom University Author-2-Name: Ibnu Harry Darmawan Author-2-Workplace-Name: Telkom University, Jl. Telekomunikasi Terusan Buah Batu, 40257, Bandung, Indonesia Author-3-Name: Irmansyah Ihsanul Kamil Author-3-Workplace-Name: Telkom University, Jl. Telekomunikasi Terusan Buah Batu, 40257, Bandung, Indonesia Author-4-Name: Author-4-Workplace-Name: Author-5-Name: Author-5-Workplace-Name: Author-6-Name: Author-6-Workplace-Name: Author-7-Name: Author-7-Workplace-Name: Author-8-Name: Author-8-Workplace-Name:) |
| Abstract: | Objective – The aim of this research is to test the correlation between the compensation variable to the performance of police hospital employees. The increasing trend of hospital patients in 2012 and 2013 indicates that competition among hospitals, particularly public hospitals, has increased. Therefore, as a hospital belonging to the classification of public hospitals, Bhayangkara Lv.(level) II Sartika Asih Bandung hospital should be able to improve its performance in order to compete with other public hospitals. Methodology/Technique – Overall achievement of performance objectives is still below target among hospitals, and the average performance on Bhayangkara Lv. II Sartika Asih Bandung hospital is no exception. This research uses descriptive research to examine 77 Bayangkara Lv.II Sartika Asih Bandung Police Hospital employees using proportional stratified random sampling. The analysis used in this research is a validity test, reliability test, simple linear regression analysis, coefficient determination, and T-test. Findings – The results of the determination coefficient test showed that compensation has an effect on employee performance (23.1% of Bhayangkara Lv. II Sartika Asih Bandung Hospital employees showed improved performance as a result of compensation). Novelty – The management of Bhayangkara Lv. II Sartika Asih Bandung Hospital should pay greater attention to the types of compensation provided to employees, to increase employee performance. |
| Keywords: | Compensation; Performance; Hospital; Employee Performance; Indonesia. |
| JEL: | M10 M11 M19 |
| Date: | 2018–04–03 |
| URL: | http://d.repec.org/n?u=RePEc:gtr:gatrjs:jmmr182&r=eff |