{"title":"Finite Sample Evaluation of Causal Machine Learning Methods: Guidelines for the Applied Researcher","authors":"A. Naghi","doi":"10.2139/ssrn.3942461","DOIUrl":"https://doi.org/10.2139/ssrn.3942461","url":null,"abstract":"The econometrics literature proposed several new causal machine learning methods (CML) in the past few years. These methods harness the strength of machine learning methods to flexibly model the relationship between the treatment, outcome and confounders, while providing valid inferential statements. Whereas numerous options are available now to the applied economics researcher, there is limited guidance on the most useful methodology for a particular applied setting. In this paper, we perform a comprehensive evaluation of the finite sample performance of recently introduced CML methods from the econometrics literature, under a wide range of data generating processes. We focus our analysis on data features that are relevant for causal inference such as varying degrees of: nonlinearity in the outcome and treatment equations, overlap, percentage of treated, alignment and heterogeneity in the treatment effect. We evaluate the methods that have received the most attention so far from the empirical economics literature: double machine learning, causal forest and the generic machine learning methods. Results on the bias, root mean squared error, coverage rates and interval lengths for the average treatment effect, group average treatment effects and individual treatment effects reveal information on the characteristics of the methods and the data features that affect their performance the most.","PeriodicalId":139983,"journal":{"name":"Econometrics: Econometric & Statistical Methods - Special Topics eJournal","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126663020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A quantum oscillator model of stock markets","authors":"D. Orrell","doi":"10.2139/ssrn.3941518","DOIUrl":"https://doi.org/10.2139/ssrn.3941518","url":null,"abstract":"This paper presents a quantum harmonic oscillator model of price fluctuations in a stock market. The model builds on a previously-published quantum model of supply and demand, and is compared with other existing quantum models of stock markets, including quantum harmonic oscillator, square-well, anharmonic oscillator, and two-state models. It can also be viewed as a quantized version of a classical econometrics model first proposed in 1933. An advantage of the approach is that it interprets market behavior in terms of entropic forces which can account for a variety of behavioral effects of the sort studied in quantum cognition and quantum decision theory. The model also helps to interpret quantities such as force, mass, frequency and energy in a financial setting. The paper uses observed price data to explore and test a hypothesis that markets act to minimize entropy.","PeriodicalId":139983,"journal":{"name":"Econometrics: Econometric & Statistical Methods - Special Topics eJournal","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132535185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Most Claimed Statistical Findings in Cross-Sectional Return Predictability Are Likely True","authors":"Andrew Y. Chen","doi":"10.2139/ssrn.3912915","DOIUrl":"https://doi.org/10.2139/ssrn.3912915","url":null,"abstract":"Harvey, Liu, and Zhu (2016) “argue that most claimed research findings in financial economics are likely false.” Surprisingly, their false discovery rate (FDR) estimates suggest most are true. I revisit their results by developing non- and semi-parametric FDR estimators that account for publication bias and empirical correlations. These estimators provide simple closed-form expressions and reliably produce an upper bound on the FDR in simulations that cluster-bootstrap from empirical predictor returns. Applying these estimators to the Chen-Zimmermann dataset of 205 predictors, I find that most claimed statistical findings in the cross-sectional predictability literature are likely true.","PeriodicalId":139983,"journal":{"name":"Econometrics: Econometric & Statistical Methods - Special Topics eJournal","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115781847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bounding Omitted Variable Bias Using Auxiliary Data","authors":"Yu-Ning Hwang","doi":"10.2139/ssrn.3866876","DOIUrl":"https://doi.org/10.2139/ssrn.3866876","url":null,"abstract":"This paper proposes a new estimator that bounds omitted variable bias using proxies for omitted variables with an asymptotically valid bootstrap procedure. The estimator is useful in many applications because it uses proxies that do not need to appear in the same dataset as the outcome variable. Many surveys include rich proxy variables for a diverse set of unobservable characteristics including abilities, beliefs, and preferences; such surveys can be used as auxiliary datasets in computing my estimator. I provide Monte Carlo simulation results that compare my estimator to the alternative estimator proposed by Pacini (2017) and to the Altonji et al. (2005) - Oster (2019) bound estimator. I show from a simulation that my estimator is robust when proxy variables are contaminated with a large amount of measurement error. I illustrate the application of my estimator in the context of a Mincerian wage regression. Last, I provide open-source software to implement the estimator and to compute the confidence interval.","PeriodicalId":139983,"journal":{"name":"Econometrics: Econometric & Statistical Methods - Special Topics eJournal","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124218894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stocking Under Random Demand and Product Variety: Exact Models and Heuristics","authors":"Vashkar Ghosh, Anand A. Paul, Lingjiong Zhu","doi":"10.1111/poms.13592","DOIUrl":"https://doi.org/10.1111/poms.13592","url":null,"abstract":"Efficient inventory management in the face of product variety is an important part of retail operations management. In this paper, we analyze the optimal stocking policy for a retailer, in a setup with a single horizontally differentiated product with an arbitrary number of product variants, stochastic demand, and two-level consumer choice. The demands for individual product variants are negatively correlated conditional on the total demand. We assume that each customer will purchase one unit of a preferred product variant, if it is in stock, and will seek to buy a second choice product, if the former is not in stock. We formulate an exact model, with Poisson customer arrivals. In order to maintain tractability and characterize an optimal policy analytically, we develop a benchmark model which does not explicitly account for the stochastic nature of customer arrival times. In this model, which is a heuristic approximation of the exact model we find simple conditions under which the objective of maximizing expected profit is jointly concave in the stocking levels of the product variants; under these conditions we prove that the optimal stocking levels are simply scaled versions of the optimal newsvendor quantities. We then analytically establish a connection between the exact and benchmark models. We develop a dynamic Monte Carlo simulation to gain further insights on the impact of different performance measures on the effectiveness of the optimal policy in the benchmark model and its performance in reference to the exact optimal policy.","PeriodicalId":139983,"journal":{"name":"Econometrics: Econometric & Statistical Methods - Special Topics eJournal","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115922597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Bradul, Larysa Varava, A. Turylo, I. Dashko, Andrii Varava
{"title":"Forecasting the Effectiveness of the Enterprise to Intensify Innovation and Investment Development, Taking into Account the Financial Component of Economic Potential","authors":"A. Bradul, Larysa Varava, A. Turylo, I. Dashko, Andrii Varava","doi":"10.15587/1729-4061.2021.239249","DOIUrl":"https://doi.org/10.15587/1729-4061.2021.239249","url":null,"abstract":"The study is devoted to the problem of analysis and forecasting of the effectiveness of the results of enterprises to ensure production and economic reserves to intensify innovation and investment development in the context of monitoring the state of their economic potential. It is the basis for the formation of endogenous and exogenous capabilities of the enterprise, aimed at achieving targeted results in each area of its activities. Creating favorable conditions for economic growth of enterprises based on the intensification of innovation and investment development requires the effective implementation of production programs using the financial component of economic potential.\u0000Based on the analysis of methodological tools for evaluating the activities of a mining and processing enterprise, formed a comprehensive methodology for quantitative and qualitative assessment of actual and projected values of performance indicators of the enterprise. It is based on determining the statistical probability of achieving a positive level of the indicator, the probability of its falling into a given interval of deviation from the recommended allowable values and an integrated assessment of the financial component of economic potential.\u0000Approbation of the developed technique is carried out within the limits of the express analysis of effective indicators of efficiency of activity of mining and processing enterprises. The results showed that with high reliability of the forecast (more than 0.85), the recommended values of the level of margin to achieve the desired efficiency are in the range of 8÷10 %. Within a sufficient level of reliability of the forecast (not less than 0.75), the recommended values of this margin are 10÷24 %. In this case, the integrated indicator of the assessment of the financial component should be more than 0.3","PeriodicalId":139983,"journal":{"name":"Econometrics: Econometric & Statistical Methods - Special Topics eJournal","volume":"70 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121013480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Equivalence between Mean Independence and Zero Correlation of the Error Term with any Function of the Covariates","authors":"Mark Stater","doi":"10.2139/ssrn.3911567","DOIUrl":"https://doi.org/10.2139/ssrn.3911567","url":null,"abstract":"This paper proves that the mean independence of the error term from the covariates in a linear regression model is equivalent to, rather than just a sufficient condition for, the error term being uncorrelated with any function of the covariates. Therefore, correct functional form specification of the conditional mean E(y|x) is equivalent to, rather than only a consequence of, the zero conditional mean assumption E(ε|x)=0. This fact may provide students and researchers with a helpful way of understanding the full logical content of this important classical linear model assumption.","PeriodicalId":139983,"journal":{"name":"Econometrics: Econometric & Statistical Methods - Special Topics eJournal","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124458044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Policy Evaluation and Temporal-Difference Learning in Continuous Time and Space: A Martingale Approach","authors":"Yanwei Jia, X. Zhou","doi":"10.2139/ssrn.3905379","DOIUrl":"https://doi.org/10.2139/ssrn.3905379","url":null,"abstract":"We propose a unified framework to study policy evaluation (PE) and the associated temporal difference (TD) methods for reinforcement learning in continuous time and space. We show that PE is equivalent to maintaining the martingale condition of a process. From this perspective, we find that the mean--square TD error approximates the quadratic variation of the martingale and thus is not a suitable objective for PE. We present two methods to use the martingale characterization for designing PE algorithms. The first one minimizes a ``martingale loss function\", whose solution is proved to be the best approximation of the true value function in the mean--square sense. This method interprets the classical gradient Monte-Carlo algorithm. The second method is based on a system of equations called the ``martingale orthogonality conditions\" with ``test functions''. Solving these equations in different ways recovers various classical TD algorithms, such as TD($lambda$), LSTD, and GTD. Different choices of test functions determine in what sense the resulting solutions approximate the true value function. Moreover, we prove that any convergent time-discretized algorithm converges to its continuous-time counterpart as the mesh size goes to zero. We demonstrate the theoretical results and corresponding algorithms with numerical experiments and applications.","PeriodicalId":139983,"journal":{"name":"Econometrics: Econometric & Statistical Methods - Special Topics eJournal","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121667637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Turan G. Bali, H. Beckmeyer, Mathis Moerke, F. Weigert
{"title":"Option Return Predictability with Machine Learning and Big Data","authors":"Turan G. Bali, H. Beckmeyer, Mathis Moerke, F. Weigert","doi":"10.2139/ssrn.3895984","DOIUrl":"https://doi.org/10.2139/ssrn.3895984","url":null,"abstract":"\u0000 Drawing upon more than 12 million observations over the period from 1996 to 2020, we find that allowing for nonlinearities significantly increases the out-of-sample performance of option and stock characteristics in predicting future option returns. The nonlinear machine learning models generate statistically and economically sizable profits in the long-short portfolios of equity options even after accounting for transaction costs. Although option-based characteristics are the most important standalone predictors, stock-based measures offer substantial incremental predictive power when considered alongside option-based characteristics. Finally, we provide compelling evidence that option return predictability is driven by informational frictions and option mispricing.","PeriodicalId":139983,"journal":{"name":"Econometrics: Econometric & Statistical Methods - Special Topics eJournal","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123923366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Application Overview Of Quantum Computing For Gas Turbine Design and Optimisation","authors":"A. Thomas Jayachandran","doi":"10.2139/ssrn.3891852","DOIUrl":"https://doi.org/10.2139/ssrn.3891852","url":null,"abstract":"Conceptual designs require optimization methods to identify the best fit in the system. The article investigates the application of quantum computation in gas turbine design and simulation problems with current technologies, approaches and potential capabilities. Quantum optimization algorithms and quantum annealers help in predicting overall efficiency and optimizing various operating parameters of the gas turbine. A comparison of both classical and quantum computers has been discussed briefly. The classical model challenges are mitigated with the use of quantum computation. A novel hybrid model for simulating gas turbines has been proposed, which consists of a combination of both physics and machine learning to eliminate few of the critical problems faced. This review elaborates application of quantum computing based machine learning for design and optimization of a gas turbine. The overall states of the gas paths of gas turbines could be analyzed using the quantum computing model in the future.","PeriodicalId":139983,"journal":{"name":"Econometrics: Econometric & Statistical Methods - Special Topics eJournal","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122553815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}