Problems with detecting assumed mediation using the hierarchical multiple regression strategy

In human resource management (HRM) and allied fields (e.g., organizational behavior, management, and industrial and organizational psychology), tests of mediation are frequently conducted using the hierarchical multiple regression (HMR) strategy of Baron and Kenny [Baron, R. M., & Kenny, D. A. (1986). The moderator–mediator variable distinction in social psychological research: Conceptual, strategic, and statistical considerations. Journal of Personality and Social Psychology, 51, 1173–1182]. Although previous research has identified a number of serious problems with this approach, the present study adds to the literature by identifying yet additional problems with its use in inferring the existence of mediation. Using a statistical simulation, we found that certain patterns of correlation coefficients guarantee inferences about mediation, whereas other patterns preclude such inferences. On the basis of various analyses including logistic regression and inspection of three-dimensional plots, we identified patterns of correlation coefficients needed to satisfy Baron and Kenny's [Baron, R. M., & Kenny, D. A. (1986). The moderator–mediator variable distinction in social psychological research: Conceptual, strategic, and statistical considerations. Journal of Personality and Social Psychology, 51, 1173–1182] conditions for inferring mediation. The same patterns have no necessary relation to actual causal connections among variables in mediation models. Moreover, as a consequence of the failure of the HMR strategy to detect mediating effects, many instances of actual mediation in HRM and allied fields may have gone undetected. In view of the foregoing, we conclude that the HMR strategy should no longer be used in testing for mediation.     

Poisson Regression for Clustered Data

We compare five methods for parameter estimation of a Poisson regression model for clustered data: (1) ordinary (naive) Poisson regression (OP), which ignores intracluster correlation, (2) Poisson regression with fixed cluster‐specific intercepts (FI), (3) a generalized estimating equations (GEE) approach with an equi‐correlation matrix, (4) an exact generalized estimating equations (EGEE) approach with an exact covariance matrix, and (5) maximum likelihood (ML). Special attention is given to the simplest case of the Poisson regression with a cluster‐specific intercept random when the asymptotic covariance matrix is obtained in closed form. We prove that methods 1–5, except GEE, produce the same estimates of slope coefficients for balanced data (an equal number of observations in each cluster and the same vectors of covariates). All five methods lead to consistent estimates of slopes but have different efficiency for unbalanced data design. It is shown that the FI approach can be derived as a limiting case of maximum likelihood when the cluster variance increases to infinity. Exact asymptotic covariance matrices are derived for each method. In terms of asymptotic efficiency, the methods split into two groups: OP & GEE and EGEE & FI & ML. Thus, contrary to the existing practice, there is no advantage in using GEE because it is substantially outperformed by EGEE and FI. In particular, EGEE does not require integration and is easy to compute with the asymptotic variances of the slope estimates close to those of the ML.     

Implementing: Alternatives,costs, and benefits

This essay provides a conceptual framework for thinking about the problem of implementing (i.e. getting things done) as part of the larger process of managing. We shall isolate some alternative approaches to that implementing problem and briefly examine the underlying beliefs, the accompanying technologies, and the attendant costs/benefits of those alternatives. We shall then make a few suggestions about appropriate alternatives for the decade ahead.     

The third post-world war II wealth bubble

Business Economics - The United States has now experienced three major wealth bubbles since 1945. The first two peaked in 1999 and 2006, followed by crash and recession. By 2018, peaks were higher...     

The unrealized value of incentivized eWOM recommendations

While companies have recognized the perceived economic benefits of encouraging and managing electronic word-of-mouth (eWOM), the benefits may be understated. Companies take into account the influence on the audience. But, what about any effects on the person who communicates the eWOM? We explore the impact that incentivized eWOM has on communicator attitude. Using the saying is believing effect as our theoretical foundation, we suggest that providing eWOM induces a change in the communicator’s attitude. By generating and providing a biased recommendation, the communicator will believe the biased recommendation. Furthermore, the communicator is likely to remember the biased recommendation and will use it to update their attitude. We examine how valence of recommendations (negative versus positive) and the number of opportunities to recommend affect the change in attitude. Our findings indicate that providing recommendations changes communicator’s attitude. Implications of the results are discussed.     

Plant Scale and Exchange‐Rate‐Induced Productivity Growth

This paper examines the impact of exchange rate movements on firm‐level productivity through changes in the scale of production. We employ plant‐level data to examine whether, and in what direction, exchange rate movements affect the scale of production, and how these changes in scale influence productivity. The paper finds that a real appreciation of the domestic currency reduces shipments and this negative effect is larger for exporters (both domestic and foreign owned). The paper also finds evidence that the appreciation‐induced reduction of scale negatively affects productivity at the plant level. This scale effect more than offsets any potential gains from the appreciation‐induced reduction in the price of imported inputs.     

Do small shareholders count?

We hypothesize that age similarity among small shareholders acts as an implicit coordinating device for their actions and, thus, could represent an indirect source of corporate governance in firms with dispersed ownership. We test this hypothesis on a sample of Swedish firms during the 1995-2000 period. Consistent with our hypothesis, we find that compared with shareholders of differing ages, same-age noncontrolling shareholders sell more aggressively following negative firm news; firms with more age-similar small shareholders are more profitable and command higher valuation; and an increase (decline) in a firm's small shareholder age similarity brings a significantly large increase (decline) in its stock price. The last effects are more pronounced in the absence of a controlling shareholder.     

A network approach to modeling the multi-echelon spare-part inventory system with backorders and interval-valued demand

A multi-echelon inventory system implies the existence of a hierarchy of stocking locations, and the dependence and interaction between them. We consider a multi-echelon, spare-part inventory management problem with outsourcing and backordering. The problem is characterized by deterministic repair time/cost, and supply and demand that lie within prescribed intervals and that vary over time. The objective is to minimize the total inventory and transportation costs. We develop a network model for problem analysis and present a network flow algorithm for solving the problem. We prove that the Wagner-Whitin property, known for the lot-sizing problem, can be extended to the spare-part inventory management problem under study.     

Value versus Growth: The International Evidence

Value stocks have higher returns than growth stocks in markets around the world. For the period 1975 through 1995, the difference between the average returns on global portfolios of high and low book-to-market stocks is 7.68 percent per year, and value stocks outperform growth stocks in twelve of thirteen major markets. An international capital asset pricing model cannot explain the value premium, but a two-factor model that includes a risk factor for relative distress captures the value premium in international returns.