Tobit models in strategy research:Critical issues and applications

Research Summary: Tobit models have been used to address several questions in management research. Reviewing existing practices and applications, we discuss three challenges: (a) assumptions about the nature of data, (b) apparent interchangeability between censoring and selection bias, and (c) potential violations of key assumptions in the distribution of residuals. Empirically analyzing the relationship between import competition and industry diversification, we contrast Tobit models with results from other estimators and show the conditions that make Tobit a suitable empirical approach. Finally, we offer suggestions and guidelines on how to use Tobit models to deal with censored data in strategy research. Managerial Summary: Data on strategic decisions often exhibit certain features, such as excess zeros and values bounded within a given range, which complicate the use of linear econometric techniques. Deriving statistical evidence in such instances may suffer from biases that undermine managerial applications. Our study presents an extensive comparison of different econometric models to deal with censored data in strategic management showing the strengths and weaknesses of each model. We also conduct an application to the context of import penetration and industry diversification to highlight how the relationship between these two variables changes depending on the econometric model used for the analysis. In conclusion, we provide a set of recommendations for scholars interested in censored data

Pay Dispersion and Executive Behaviour:Evidence from Innovation

Compensation packages are widely used to motivate top executives. Pay dispersion among a firm’s executives, however, can be associated with the antithetic effects of social comparison and individual motivation, with unclear implications for the company. We focus on innovation activities, which represent an important channel through which pay dispersion can affect firm performance, and test our predictions by exploring innovative output as a function of executives’ pay dispersion in a panel of US firms. We find that executive pay dispersion acts as a double-edged sword: on the one hand, the higher the dispersion in variable pay, the higher the innovation. On the other hand, the larger the dispersion in fixed pay, the lower the innovation. Results are robust to a number of tests, such as restricting the analysis to executives with direct responsibility for innovation projects and considering individual incentives in the form of cash pay

tobit models in strategy research critical issues and applications

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Microstructural brain abnormalities, affective temperaments, and suicidal behavior in patients with major depression

According to magnetic resonance imaging (MRI) studies, brain white matter (WM) abnormalities have been suggested to play a critical role in the pathogenesis of major depressive disorder (MDD) and related suicidal behavior. However, MRI findings may be limited by low spatial resolution; therefore, an important contribution to the understanding of the role and significance of WM alterations derived by the development of the most recent magnetic resonance techniques, such as diffusion tensor imaging (DTI). Several DTI studies reported an association between altered WM integrity and MDD/suicidal behavior. Microstructural WM abnormalities may be located in neural circuits critically implicated in emotional processes and mood regulation resulting in enhanced vulnerability to psychiatric morbidity. WM abnormalities detected using DTI may contribute to functional deficits and help to clarify the pathophysiological mechanisms underlying MDD as well as suicidal behavior. By a clinical point of view, research also suggested that affective temperaments may play a relevant role in the psychopathological characteristics of mood disorders, clinical trajectory of episodes and polarity, long-term outcome and suicidality. Unfortunately, only few studies investigated the association between affective temperaments and WM abnormalities and discussed their possible implications in patients with MDD and suicidal behavior. Using a comprehensive search of Medline database, the aim of the present study was to critically review the current literature on the association between WM alterations as assessed by MRI and DTI techniques, affective temperaments, MDD and suicidal behavior

the role of glutamate excitotoxicity and neuroinflammation in depression and suicidal behavior focus on microglia cells

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Essays on Empirical Corporate Finance

The effect of corporate governance and managers on the value of companies has received great attention in the recent public debate. In the academic research, this increased attention has been associated with an effort to develop finer conceptual frameworks and analytical techniques to assess how governance and financial characteristics influence corporate policies and profitability. While theoretical models represent a successful approach under specific hypotheses, the econometric analysis of corporate governance and managerial characteristics has proven to be extremely challenging. Because governance and managerial characteristics are equilibrium outcomes largely determined by the firm itself, it is methodologically difficult to separate out their determinants from their consequences to infer causal effects. Since its infancy the empirical corporate governance and corporate finance research has faced this problem, which is often responsible for mixed empirical results. In my dissertation, I adopt a common methodological framework developed in the “program evaluation” literature to shed new light on the effects of governance and managerial characteristics on a variety of corporate policies and, ultimately, firm performance. In particular, I estimate a class of difference-in-differences models deriving the empirical identifications from policy changes that generate “quasi-natural experiments”

Micro venture capital

Recently, the venture capital (VC) industry has experienced the entry of several new capital providers. Using US data on investors and their portfolio startups from 2000 to 2022, we document the emergence of a new type of investors: the micro VC. Our analysis reveals that micro Vencture Capitalists (VCs) have an idiosyncratic investment strategy, which differs from traditional VCs. Compared with these investors, micro VCs invest in riskier startups, that is, early-stage ventures initiated by less experienced founders; yet, micro VCs are less likely to syndicate, stage their investments, and replace the startup founders. Additionally, startups funded by micro VCs are less likely to experience successful exits than those backed by traditional VCs. These results can be traced to a mix of smaller capital endowments, less sophisticated limited partners, and lesser human capital of which micro VCs dispose, and that may induce them to spread their thin capital across many investments to maximize returns. Our analysis also uncovers important differences in the strategies pursued by micro VCs and business angels.Managerial SummaryThe VC industry is increasingly populated by a variety of investors with disparate characteristics and objectives. One such type of investors is represented by the so-called micro VC firms. These are VC firms that manage funds typically below $50 million and focused primarily on investing in founder-led startups. We leverage comprehensive VC data in the United States to answer three questions: (1) Who leads micro VC firms? (2) How do micro VC firms invest? (3) How do startups backed by micro VC perform? We find that micro VC firms are often led by relatively inexperienced entrepreneurs with little VC experience, and these firms are supported by less sophisticated limited partners. Although micro VC firms invest in riskier startups, they are less engaged in syndication and investment staging than traditional VC firms. Finally, micro VC-backed startups have a lower probability of successful exit as compared with those backed by traditional VC firms. Collectively, our results suggest that micro VCs differ from traditional VCs beyond being "micro.

White matter abnormalities : Insights into the pathophysiology of major affective disorders

Abstract The presence of white matter hyperintensities (WMHs) has been commonly associated with poor outcome in subjects with major affective disorders. Unfortunately, WMHs may be frequently confounded by the use of psychoactive medications and duration of illness. Although findings from the current literature are quite conflicting, we proposed that subjects with WMHs may be at higher suicidal risk when compared to other subgroups without. Based on the Fazekas modified scale, the severity of WMHs may serve as a trait marker of disease. Interestingly, the presence of WMHs may represent a neurobiological marker between the underlying vulnerability and clinical presentation of major affective disorders