scholarly journals The Use of Structural Models in Econometrics

2017 ◽  
Vol 31 (2) ◽  
pp. 33-58 ◽  
Author(s):  
Hamish Low ◽  
Costas Meghir
Keyword(s):  
Structural Model ◽  
Policy Design ◽  
Structural Estimation ◽  
Structural Models ◽  
Reduced Form ◽  
Randomized Experiments ◽  
Dynamic Stochastic ◽  
Structural Econometric Model ◽  
Structural Econometric

This paper discusses the role of structural economic models in empirical analysis and policy design. The central payoff of a structural econometric model is that it allows an empirical researcher to go beyond the conclusions of a more conventional empirical study that provides reduced-form causal relationships. Structural models identify mechanisms that determine outcomes and are designed to analyze counterfactual policies, quantifying impacts on specific outcomes as well as effects in the short and longer run. We start by defining structural models, distinguishing between those that are fully specified and those that are partially specified. We contrast the treatment effects approach with structural models, and present an example of how a structural model is specified and the particular choices that were made. We cover combining structural estimation with randomized experiments. We then turn to numerical techniques for solving dynamic stochastic models that are often used in structural estimation, again with an example. The penultimate section focuses on issues of estimation using the method of moments.

scholarly journals An improved structural model of the human iron exporter ferroportin. Insight into the role of pathogenic mutations in hereditary hemochromatosis type 4

2017 ◽  
Vol 13 (4) ◽  
Author(s):  
Valentina Tortosa ◽  
Maria Carmela Bonaccorsi di Patti ◽  
Valentina Brandi ◽  
Giovanni Musci ◽  
Fabio Polticelli
Keyword(s):  
Membrane Protein ◽  
Crystal Structures ◽  
Iron Homeostasis ◽  
Structural Model ◽  
Hereditary Hemochromatosis ◽  
Structural Models ◽  
Pivotal Role ◽  
Cellular Iron ◽  
Insight Into

AbstractFerroportin (Fpn) is a membrane protein representing the major cellular iron exporter, essential for metal translocation from cells into plasma. Despite its pivotal role in human iron homeostasis, many questions on Fpn structure and biology remain unanswered. In this work, we present two novel and more reliable structural models of human Fpn (hFpn; inward-facing and outward-facing conformations) obtained using as templates the recently solved crystal structures of a bacterial homologue of hFpn,

Methodology of Macroeconometrics

2021 ◽  
Author(s):  
Aris Spanos
Keyword(s):  
Curve Fitting ◽  
Goodness Of Fit ◽  
Structural Model ◽  
Time Series Data ◽  
Structural Models ◽  
Empirical Modeling ◽  
Series Data ◽  
Modeling Framework ◽  
Learning From Data ◽  
Dynamic Stochastic

The current discontent with the dominant macroeconomic theory paradigm, known as Dynamic Stochastic General Equilibrium (DSGE) models, calls for an appraisal of the methods and strategies employed in studying and modeling macroeconomic phenomena using aggregate time series data. The appraisal pertains to the effectiveness of these methods and strategies in accomplishing the primary objective of empirical modeling: to learn from data about phenomena of interest. The co-occurring developments in macroeconomics and econometrics since the 1930s provides the backdrop for the appraisal with the Keynes vs. Tinbergen controversy at center stage. The overall appraisal is that the DSGE paradigm gives rise to estimated structural models that are both statistically and substantively misspecified, yielding untrustworthy evidence that contribute very little, if anything, to real learning from data about macroeconomic phenomena. A primary contributor to the untrustworthiness of evidence is the traditional econometric perspective of viewing empirical modeling as curve-fitting (structural models), guided by impromptu error term assumptions, and evaluated on goodness-of-fit grounds. Regrettably, excellent fit is neither necessary nor sufficient for the reliability of inference and the trustworthiness of the ensuing evidence. Recommendations on how to improve the trustworthiness of empirical evidence revolve around a broader model-based (non-curve-fitting) modeling framework, that attributes cardinal roles to both theory and data without undermining the credibleness of either source of information. Two crucial distinctions hold the key to securing the trusworthiness of evidence. The first distinguishes between modeling (specification, misspeification testing, respecification, and inference), and the second between a substantive (structural) and a statistical model (the probabilistic assumptions imposed on the particular data). This enables one to establish statistical adequacy (the validity of these assumptions) before relating it to the structural model and posing questions of interest to the data. The greatest enemy of learning from data about macroeconomic phenomena is not the absence of an alternative and more coherent empirical modeling framework, but the illusion that foisting highly formal structural models on the data can give rise to such learning just because their construction and curve-fitting rely on seemingly sophisticated tools. Regrettably, applying sophisticated tools to a statistically and substantively misspecified DSGE model does nothing to restore the trustworthiness of the evidence stemming from it.

Improving Audio Spatialization Using Customizable Pinna Based Anthropometric Model of Head-Related Transfer Functions

2012 ◽  
pp. 81-100
Author(s):  
Navarun Gupta ◽  
Armando Barreto
Keyword(s):  
Structural Model ◽  
Transfer Functions ◽  
Structural Models ◽  
Model Parameters ◽  
Digital Audio ◽  
Sound Sources ◽  
Predictive Equations ◽  
Listening Tests ◽  
Anthropometric Features

The role of binaural and immersive sound is becoming crucial in virtual reality and HCI related systems. This chapter proposes a structural model for the pinna, to be used as a block within structural models for the synthesis of Head-Related Transfer Functions, needed for digital audio spatialization. An anthropometrically plausible pinna model is presented, justified and verified by comparison with measured Head-Related Impulse Responses (HRIRs). Similarity levels better than 90% are found in this comparison. Further, the relationships between key anthropometric features of the listener and the parameters of the model are established, as sets of predictive equations. Modeled HRIRs are obtained substituting anthropometric features measured from 10 volunteers into the predictive equations to find the model parameters. These modeled HRIRs are used in listening tests by the subjects to assess the elevation of spatialized sound sources. The modeled HRIRs yielded a smaller average elevation error (29.9o) than “generic” HRIRs (31.4o), but higher than the individually measured HRIRs for the subjects (23.7o).

Distinguishing among Competing Theories of the Market Share Effect

1988 ◽  
Vol 52 (4) ◽  
pp. 68-80 ◽  
Author(s):  
Robert Jacobson
Keyword(s):  
Market Share ◽  
Structural Model ◽  
Empirical Studies ◽  
Reduced Form ◽  
Bivariate Correlation ◽  
Form Model ◽  
Reduced Form Model ◽  
Unobservable Factors ◽  
Direct Market

Empirical studies assessing the role of market share in influencing profitability have been challenged because of their inability to distinguish among competing hypotheses. The author addresses this concern by estimating a reduced form model of profitability. The estimated reduced form, producing market share coefficients indistinguishable from zero, is consistent with an underlying structural model with no direct market share effect. The bivariate correlation between market share and ROI arises primarily from a failure to control for the unobservable factors contemporaneously influencing both variables and inducing serial correlation in ROI models. An alternative structural model that both contains a substantial market share effect and is consistent with the estimated reduced form is not apparent.

The Limits of Inference with Theory: A Review of Wolpin (2013)

2014 ◽  
Vol 52 (3) ◽  
pp. 820-850 ◽  
Author(s):  
John Rust
Keyword(s):  
Economic Theory ◽  
Ad Hoc ◽  
Empirical Work ◽  
Identification Problem ◽  
Randomized Experiments ◽  
Basic Premise ◽  
Economic Theories ◽  
Econometric Approach ◽  
Structural Econometric

This essay reviews Kenneth I. Wolpin's (2013) monograph The Limits of Inference without Theory, which arose from lectures he presented at the Cowles Foundation in 2010 in honor of Tjalling Koopmans. While I readily agree with Wolpin's basic premise that empirical work that eschews the role of economic theory faces unnecessary self-imposed limits relative to empirical work that embraces and tries to test and improve economic theory, it is important to be aware that the use of economic theory is not a panacea. I point out that there are also serious limits to inference with theory: 1) there may be no truly “structural” (policy invariant) parameters, a key assumption underpinning the structural econometric approach that Wolpin and the Cowles Foundation have championed; 2) there is a curse of dimensionality that makes it very difficult for us to elucidate the detailed implications of economic theories, which is necessary to empirically implement and test these theories; 3) there is an identification problem that makes it impossible to decide between competing theories without imposing ad hoc auxiliary assumptions (such as parametric functional form assumptions); and 4) there is a problem of multiplicity and indeterminacy of equilibria that limits the predictive empirical content of many economic theories. I conclude that though these are very challenging problems, I agree with Wolpin and the Cowles Foundation that economists have far more to gain by trying to incorporate economic theory into empirical work and test and improve our theories than by rejecting theory and presuming that all interesting economic issues can be answered by well-designed controlled, randomized experiments and assuming that difficult questions of causality and evaluation of alternative hypothetical policies can be resolved by simply allowing the “data to speak for itself.” (JEL B41, C18)

scholarly journals Uncovering Stakeholder Participation in Payment for Hydrological Services (PHS) Program Decision making in Mexico and Colombia

2021 ◽  
Vol 13 (15) ◽  
pp. 8562
Author(s):  
Andres M. Urcuqui-Bustamante ◽  
Theresa L. Selfa ◽  
Paul Hirsch ◽  
Catherine M. Ashcraft
Keyword(s):  
Stakeholder Engagement ◽  
Program Effectiveness ◽  
Policy Design ◽  
Stakeholder Participation ◽  
Market Mechanism ◽  
Non Profit ◽  
Program Administrators ◽  
Water Users ◽  
Hydrological Services

Payment for ecosystem services (PES) is a market-based policy approach intended to foster land use practices, such as forest conservation or restoration, that protect and improve the benefits from healthy, functioning ecosystems. While PES programs are used globally, they are an especially prominent environmental policy tool in Latin America, where the vast majority are payment for hydrological services (PHS) programs, which incentivize the conservation and restoration of ecosystems associated with water production and clean water for clearly defined water users. As a market mechanism, PHS approaches involve a transactional relationship between upstream and downstream water users who are connected by a shared watershed. While existing literature has highlighted the important role of non-state actors in natural resource management and program effectiveness, few studies have explored the role of stakeholder participation in the context of PHS programs. Building on the collaborative learning approach and the Trinity of Voice framework, we sought to understand how and to what extent PHS program stakeholders are engaged in PHS design, implementation, and evaluation. In this paper we explored (1) the modes of stakeholder engagement in PHS programs that program administrators use, and (2) the degree to which different modes of stakeholder participation allow PHS stakeholders to have decision power with which to influence PHS policy design and expected outcomes. To better understand the role of stakeholder participation, and the different ways participation occurs, we used a comparative multiple-case study analysis of three PHS program administration types (government, non-profit, and a mixed public–private organization) in Mexico and Colombia that have incorporated stakeholder engagement to achieve ecological and social goals. Our analysis draws on institutional interviews to investigate the modes of stakeholder engagement and understand the degree of decision space that is shared with other PHS stakeholders. Across all cases, we found that the trust between key actors and institutions is an essential but underappreciated aspect of successful collaboration within PHS initiatives. We conclude with recommendations for ways in which program administrators and governmental agencies can better understand and facilitate the development of trust in PHS design and implementation, and natural resources management more broadly.

scholarly journals Policy-relevant insights for regional renewable energy deployment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Carla De Laurentis ◽  
Peter J. G. Pearson
Keyword(s):  
Renewable Energy ◽  
Policy Design ◽  
Comparative Case Study ◽  
Geographical Differences ◽  
Governance Capacity ◽  
Policy Makers ◽  
Case Study Analysis ◽  
Documentary Analysis ◽  
The Uk

Abstract Background The paper explores how regional actors engage with energy systems, flows and infrastructures in order to meet particular goals and offers a fine-tuned analysis of how differences arise, highlighting the policy-relevant insights that emerge. Methods Using a novel framework, the research performs a comparative case study analysis of three regions in Italy and two of the devolved territories of the UK, Wales and Scotland, drawing on interviews and documentary analysis. Results The paper shows that acknowledging the socio-materialities of renewable energy allows a fine-tuned analysis of how institutions, governance and infrastructure can enable/constrain energy transitions and policy effectiveness at local and regional levels. The heuristic adopted highlights (i) the institutions that matter for renewable energy and their varied effects on regional renewable energy deployment; (ii) the range of agencies involved in strategically establishing, contesting and reproducing institutions, expectations, visions and infrastructure as renewable energy deployment unfolds at the regional level and (iii) the nature and extent of infrastructure requirements for and constraints on renewable energy delivery and how they affect the regional capacity to shape infrastructure networks and facilitate renewable energy deployment. The paper shows how the regions investigated developed their institutional and governance capacity and made use of targets, energy visions and spatial planning to promote renewable energy deployment. It shows that several mediating factors emerge from examining the interactions between regional physical resource endowments and energy infrastructure renewal and expansion. The analysis leads to policy-relevant insights into what makes for renewable energy deployment. Conclusion The paper contributes to research that demonstrates the role of institutional variations and governance as foundations for geographical differences in the adoption of renewable energy, and carries significant implications for policy thinking and implementation. It shows why and how policy-makers need to be more effective in balancing the range of goals/interests for renewable energy deployment with the peculiarities and specificities of the regional contexts and their infrastructures. The insights presented help to explain how energy choices and outcomes are shaped in particular places, how differences arise and operate in practice, and how they need to be taken into account in policy design, policy-making and implementation.

Spirituality in patients with advanced illness: The role of symptom control, resilience and social network

2016 ◽  
Vol 21 (12) ◽  
pp. 2765-2774 ◽  
Author(s):  
Miguel Fombuena ◽  
Laura Galiana ◽  
Pilar Barreto ◽  
Amparo Oliver ◽  
Antonio Pascual ◽  
...  
Keyword(s):  
Social Support ◽  
Structural Model ◽  
Symptom Control ◽  
Cross Sectional Study ◽  
Physical Symptoms ◽  
Advanced Illness ◽  
Cross Sectional ◽  
Palliative Care Teams ◽  
Symptomatic Control

In this study, we analyzed the relationships among clinical, emotional, social, and spiritual dimensions of patients with advanced illness. It was a cross-sectional study, with a sample of 108 patients in an advanced illness situation attended by palliative care teams. Statistically significant correlations were found between some dimensions of spirituality and poor symptomatic control, resiliency, and social support. In the structural model, three variables predicted spirituality: having physical symptoms as the main source of discomfort, resiliency, and social support. This work highlights the relevance of the relationships among spirituality and other aspects of the patient at the end of life.

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