robustness in economics

/CapHeight 662 It concludes that it is a mistake to equate self-sufficiency with robustness – putting all the eggs in one basket is still not a good idea. We also consider standard models of aggregation and segregation among agent communities, as well as the tactical and strategic associations of agents with common interests. Variables within the panel-VAR are estimated alphas by country and by year (from Table 8); z-score = (average return on assets + equity/assets)/(standard deviation of the return on assets); FR-regulation = Fraser Index on market regulation; Supervision = index measuring official disciplinary power. /Leading 150 Although, in principle, such a method would provide evidence on the credibility of any particular set of findings, the number of assumptions in these models, their computational burden, and disagreements among researchers as to the a priori importance of particular assumptions, has led practitioners to limit the use of this approach.160 That is not to say that evidence accumulated from the estimation of models by different researchers, each with different modeling inclinations, is not valuable.161 Indeed, contradicting findings could be very revealing. Indeed, an approach that fails to reflect such underlying instability risks violating the goals for a reasonable return on capital discussed in Chapter 2. There are other sense of robust that are often used and are somewhat related: robust to heteroskedasticity or autocorrelation, outliers, and various assumption violations (like error distributions). /MissingWidth 278 The effect of a one standard deviation shock of the Fraser regulation index on alpha is negative; the same applies for the z-score variable.22 Table 11 presents VDCs and reports the total effect accumulated over 10 and 20 years. stream A model is deemed invalid if it is rejected according to some statistical criterion. Jamie O’Brien, in Shaping Knowledge, 2014. Hypothesis testing as a means of model validation or selection is eschewed because, given enough data, all models would be rejected as true models. Some governments assert that global value chains create economic vulnerabilities in times of a pandemic. In contrast, in the absolutist view, a model would be considered useful for prediction only if it were not rejected on statistical grounds, even though non-rejection does not necessarily imply predicted effects will be close to actual effects. 3, the effect of a one standard deviation shock of the domestic credit to the private sector ratio on alpha is negative, as is the sovereign risk variable. Robustness is recognized as a ubiquitous system property in many fields ranging from biological systems and economics to computer science and control systems [1] [2] [3][4]. If the coefficients are plausible and robust, this is commonly interpreted as evidence of structural validity. Surprisingly, philosophers of economics have only recently become interested in robustness. In economics, robustness is attributed to financial markets that continue to perform despite alterations in market conditions. Robustness definition at Dictionary.com, a free online dictionary with pronunciation, synonyms and translation. As a robustness test and in order to deal with potential issues of endogeneity bias, we also employ a panel-VAR model to examine the relationship between bank management preferences and various banking sector characteristics.19 The main advantage of this methodology is that all variables enter as endogenous within a system of equations, which enables us to reveal the underlying causality among them.20 We specify a panel-VAR model where the key variable is alpha, the shape parameter of the managerial behavior function; we also include the main right side variables of the previous section. /XHeight 519 Wanting robustness in insurance: A model of catastrophe risk pricing and its empirical test @article{Zhu2017WantingRI, title={Wanting robustness in insurance: A model of catastrophe risk pricing and its empirical test}, author={W. Zhu}, journal={Insurance Mathematics & Economics}, year={2017}, volume={77}, pages={14-23} } The validation exercise exploited data that were unavailable at the time of estimation to validate their model. << /Subtype /TrueType 2���c��$��e���6��h��E� z)�M�8V/�^ȫ��^z��4J���R����e)�U�8P0���$B0EeLE�DE�Y}��,�N�jW�C ���(��VmZ�!l���ÞL.qyVW���V��u��R�z�)Lh�����ꩋ�^K�gaj4�'a^��Y�_�$��8t������#������'�� �K)d?s��QZ=W��aN2�lŪ�*/s.-��@Xƌ́8rW��܄sPsyd0h��c,U�.Q�ܭ���Q�������0P&� �4�Zz~l�y�k`ݛy��K�4���aa�- nw5�Q����f�O?c�, �ͩ�����;�؃��x�P�L�I����T#¸s��g�Y2�D��&=�i�[7^�d�yY��i����mU*Mn��{1O=���vt0%. /Subtype /TrueType Re: Robustness of an economy: Quoted from this wikipedia article: "robustness is the ability of a financial trading system to remain effective under different markets and different market conditions" Effectiveness is the key concept in this definition. U(� �|�+u�Dq̋,�ՠ�A��� 4ܵ�9�n����8����8�f��;�,؉�7cG������~��' /Subtype /TrueType For exam-ple, of the 98 papers published in The American Economic Review during 2009, 76 involve some data analysis. If T is above 0.841, the returns are said to be significantly positive at the critical threshold of 20 per cent (that is, 5 per cent and 20 per cent probability, respectively, that this conclusion is incorrect). Impulse response functions (IRFs)—alpha, Fraser regulation, supervision index, z-score. There are two approaches to model validation, stemming from different epistemological perspectives. << Across the board, the three indicators happen to be significant with the right sign in the vast majority of cases. The aim of the conference, “Robustness in Economics and Econometrics,” is to bring together researchers engaged in … The formula of the Sharpe ratio is: with R¯ the annualized return of the trading rule, Rf, the annualized risk free returns of the asset under management, and σR annualized standard deviation of (daily) rule returns. /ItalicAngle 0 The results, therefore, are robust. 6 0 obj The information considered was hand-collected and highly confidential. Table 12. Look it up now! As advocated by Bird et al. /Encoding /WinAnsiEncoding Imad Moosa, Vikash Ramiah, in Emerging Markets and the Global Economy, 2014. First, the ways in which contracts between investors are negotiated in respect of preplanned exit behavior might be a fruitful avenue of further theoretical and empirical work. This strength is purchased at a cost. ‎This book focuses on general frameworks for modeling heavy-tailed distributions in economics, finance, econometrics, statistics, risk management and insurance. ADF1 assumes an autoregressive model for the residual, ADF2 assumes an autoregressive model with drift, and ADF3 assumes an autoregressive model with drift and trend stationary. 10 0 obj /FirstChar 32 Using only the control villages, they estimated a behavioral model of parental decisions about child schooling and work, as well as family fertility. 250 0 0 0 0 0 0 0 0 0 0 0 333 333 0 0 Robustness refers to the ability of a model to estimate the cost of capital reliably even when different economic conditions may influence its inputs and implementation, or when the model's assumptions are not fully satisfied. Robustness in economics Economics is not so much concerned with experimentation or measurement as with building analytically solvable mathematical models. /Ascent 891 The results are reported in Table 6.5. At the same time, sharp increases in the allowed rate of return create problems for customers. Is it the case that the cost of capital has changed significantly, or is it a problem with the models and how they are implemented in the current environment? multiple robustness tests the uncertainty likely increases. These factors did not materially impact the analysis of the variables already considered. Only the signs of the residuals matter in determining the quantile regression estimates, and thus outlying responses influence the fit in so far as they are either above or below the fitted hyperplane, but how far above or below is irrelevant. We use cookies to help provide and enhance our service and tailor content and ads. Note: Table presents the variance decompositions (VDC), which show the components of the forecasts error variance of all variables within the panel-VAR. This process of repeated model pre-testing invalidates the application of standard formal statistical tests. However, this approach is time-consuming and potentially expensive to implement. From: Risk and Return for Regulated Industries, 2017, R. Koenker, in International Encyclopedia of the Social & Behavioral Sciences, 2001. /Flags 32 Abstract. << Examples are pervasive, appearing in almost every area of applied econometrics. 0 0 0 0 722 0 611 0 0 0 0 0 0 0 0 0 Robustness analysis in economics is thus usually a special, degenerate form of general robustness analysis as Wimsatt defines it: checking the robustness of a result with respect to a limited set of modelling assumptions that are usually plainly unrealistic. /Leading 150 Variables within the panel-VAR are estimated alphas by country and by year (from Table 5); HHI = logarithm of Herfindahl Index; DCPC = logarithm of the domestic credit to the private sector as a percent of GDP; sovereign = sovereign lending rate. We may also expect, however, that firms will not get financed in the latter case where the venture capitalist’s preplanned exit strategy is toward an acquisition and an entrepreneur does not want to give up control rights. The estimates and the associated inference apparatus have an inherent distribution-free character since quantile estimation is influenced only by the local behavior of the conditional distribution of the response near the specified quantile. ADF1 assumes an autoregressive model for the residual, ADF2 assumes an autoregressive model with drift, and ADF3 assumes an autoregressive model with drift and trend stationary. The answer is likely to vary by country. It has been shown that since investors are, generally speaking, risk averse, a good measure of performance would be the ratio of reward per unit of risk taken (Murphy, 1986). In econometrics, both problems appear, usually together, and it is useful to refer to th e treatment of both problem s in economic applications as robust econometrics. << The chapter introduces difficulties in seeking optimal solutions to the problems of distribution, especially where agents have formed interest groups, and outline some methods for achieving effective decisions in the face of bias and prejudice. We report the results of a regression where the dependent variable is the conditional volatility of the CAR. This book focuses on general frameworks for modeling heavy-tailed distributions in economics, finance, econometrics, statistics, risk management and insurance. Thus, one criterion for model validation/selection that fits within the “pragmatic” view is to examine a model’s predictive accuracy, namely, how successful the model is at predicting outcomes of interest within the particular context for which the model was designed. Looking at evidence from a number of models remains the best practice. << When using the ICS as a measure of market conditions, the impact is always negative and statistically significant, even when one controls for the persistency of the conditional volatility. Although these models tend to have a lot of parameters, sometimes numbering into the hundreds, given the extensiveness of the data moments that these models attempt to fit, the models are actually parsimonious. This book presents recent research on robustness in econometrics. /Widths [ 250 0 0 0 0 0 0 214 0 0 0 0 250 0 We do not know the “true” model of the cost of capital, so it is useful to consider evidence from all reasonable models, while recognizing their strengths and weaknesses and paying close attention to how they were implemented. /Ascent 905 Specifically, if p and p∗ are related by the long-run relation: and if they are cointegrated such that εt∼I(0), then equation (6) is misspecified and the correctly specified model is an error correction model of the form: where θ is the coefficient on the error correction term, which should be significantly negative for the model to be valid. In the experiment, families that met an income eligibility criterion were randomly assigned to control and treatment groups. 0 444 0 722 667 667 722 611 556 722 722 333 389 722 611 889 Setting rates based on a transitory blip (up or down) in the cost of capital can lead to rates that will be expected to provide too much or too little return over most of the rate's life (before the next rate setting). The validity of the model was then assessed according to how well it could forecast (predict) the behavior of households in the treatment villages.162. It is tempting to dismiss the approach for that reason, although we see no other empirical methodology with which to replace it. Only in 6 of 223 cases were differences observed (where the syndicated investor used common equity or warrants when the respondent investor used a security involving debt and/or preferred equity). 3. First of all, while the size of the conditional volatility does depend upon the window's size, the time series behavior of the conditional volatility is more or less the same as shown in Figure 6.3. HHI = logarithm of Herfindahl Index; DCPC = logarithm of the domestic credit to the private sector as a percent of GDP; sovereign = sovereign lending rate. /Length 3184 To evaluate the robustness of our results, we use the Student t-statistic which is generally accepted by academics and practitioners to test the hypothesis that the returns generated by technical analysis are zero. /ItalicAngle 0 Variables within the panel-VAR are estimated alphas by country and by year (from Tables 5 and 6). The second robustness check we performed is related to the particular type of CSR. Copyright © 2020 Elsevier B.V. or its licensors or contributors. << The ambitiousness of the research agenda that the DCDP approach can accommodate is a major strength. (2007) and Drusch and Lioui (2010), CSR event type is likely to matter for the impact of CSR on firm value. /BaseFont /TimesNewRomanPSMT Our dataset provided some new control variables for entrepreneurial firm quality and venture capital fund quality; future work might consider more refined control variables with more detailed data. Shows the economic consequences of observed heavy-tailed risk distributions in the fields of economics, finance and insurance. If the unusual circumstances are instead believed to be temporary, the regulator may wish to take this into account in setting rates that will be reasonable over the entire regulatory period. In general, a system … 500 500 500 500 389 389 278 500 444 667 444 444 389]>> During the early 2000s, the DCF model, covered in Chapter 5, was subject to substantial criticism related to allegations of bias in analysts' earnings per share forecasts.9 Similarly, the risk premium model has produced very different results in times of high and low inflation, however, these swings in the model results do not necessarily reflect actual changes in the true cost of capital. (2008) and Moosa (2011). Regardless, as discussed we were unable to empirically distinguish between these two themes due to an inability to obtain details from the investors as to when the preplanned exit strategy was revealed to the entrepreneur (the vast majority of the venture capitalists did not want to disclose this information). Halbert White Xun Lu Department of Economics University of California, San Diego June 18, 2010 Abstract A common exercise in empirical studies is a "robustness check," where the researcher examines how certain "core" regression coe¢ cient estimates behave when the regression speci–cation is modi–ed by adding or removing regressors. Further theoretical work in the spirit of Casamatta and Haritchabalet (2007) and empirical work in the spirit of Lerner (1994a,b)Lerner (1994a)Lerner (1994b), Lockett and Wright (2001), and Gompers (1995) could consider staging and syndication vis-à-vis preplanned exits; those topics are beyond the scope of this chapter. 8 0 obj Some researchers have deliberately held out data to use for validation purposes. This is because the measure of risk (standard deviation) that they both use is independent on the order of the data. More recently, Todd and Wolpin (2006) used data from a large-scale school subsidy experiment in Mexico, where villages were randomly assigned to control and treatment groups. 541 0 0 0 0 0 0 1000 0 0 0 0 0 0 0 0 For example, one may assume that a linear regression model has normal errors, so the question may be how sensitivity is the Ordinary Least Squares (OLS) estimator to the assumption of normality. A better alternative might be to set rates on the current estimates and provide an efficient mechanism by which rates can be adjusted as the cost of capital returns to a more normal state. It deserves a page of its own. ADF, Augmented Dickey Fuller; Adj., adjusted. Second, recall (Section 12.2) that our intuition linking preplanned exits to contracts involved two themes: one involved the venture capitalist disclosing to the entrepreneur the exit strategy, and the other did not. So, at best, robustness checks “some” assumptions for how they impact the conclusions, and at worst, robustness becomes just another form of the garden of forked paths. Broll et al. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Robustness Checks: Changing the Event Window. The book also discusses Third, other variables considered but not explicitly reported included portfolio size per manager and tax differences across countries (in the spirit of Kanniainen and Keuschnigg, 2003, 2004Kanniainen and Keuschnigg, 2003Kanniainen and Keuschnigg, 2004; Keuschnigg, 2004; Keuschnigg and Nielsen, 2001, 2003a,b, 2004a,bKeuschnigg and Nielsen, 2001Keuschnigg and Nielsen, 2003aKeuschnigg and Nielsen, 2003bKeuschnigg and Nielsen, 2004aKeuschnigg and Nielsen, 2004b). /Type /Font /StemH 77 A central theme is that of (non-)robustness, i.e., the fact that the presence of heavy tails can either reinforce or reverse the implications of a number of models in these fields, depending on the degree of heavy-tailed ness. This assumes that the decision maker trusts the model completely. Variance Decomposition Estimations for Alpha, Fraser Regulation, Supervision Index, z-Score. I think this is related to the commonly used (at least in economics) idea of “these results hold, after accounting for … endobj Looking at the first row of Fig. 0 0 0 556 611 556 611 556 333 611 611 278 0 556 278 889 We controlled for a very large number of different firm-specific and private investor-specific characteristics, market conditions, and institutional factors. The first was to control for the window length. Some regulators (e.g., the US Surface Transportation Board) have explicitly determined a numerical weight to assign to each model result, while others use a range of estimates to guide their decision. 7 0 obj For each regression we report three tests of the presence of a unit root in the residual of the regressions. D. Wade Hands Derivational Robustness, Credible Substitute Systems, and Mathematical Economic Models: The Case of Stability Analysis in Walrasian General Equilibrium Theory, SSRN Electronic Journal (Jan 2014). Robustness to assumptions: One method is to check how robust the empirical findings are to alternative assumptions. /CapHeight 716 This book focuses on general frameworks for modeling heavy-tailed distributions in economics, finance, econometrics, statistics, risk management and insurance. 1. Re: Robustness of an economy: Quoted from this wikipedia article: "robustness is the ability of a financial trading system to remain effective under different markets and different market conditions" Effectiveness is the key concept in this definition. Our “robust” decision maker wants to know how well a given rule will work when he does not know a single transition law $ \ldots $. /MissingWidth 250 /Type /Font The robustness of models of socio-spatial change, based on innovative knowledge, depends on the sophistication of the design and deployment of its agents. Ghosh (1993) concluded that a smaller than optimal futures position is undertaken when the cointegrating relation is unduly ignored, attributing the under-hedge results to model misspecification. As advocated by previous literature, this length may be of importance. Can one provide convincing evidence about the credibility of these exercises? All economic models involve abstractions and idealisations. Further empirical work in this regard might also consider sources of funds in the spirit of Mayer et al. /Ascent 891 No matter which procedure is used, the hedge is highly effective in the case of the UK and ineffective in the case of Japan—the difference lies in return correlations, not the estimation methods. This book presents recent research on robustness in econometrics. Impulse response functions (IRFs)—alpha, Herfindahl Index, domestic credit to the private sector and sovereign risk. The cumulative abnormal return conditional volatility for different windows. One consideration is whether the instability is generally expected to abate during the regulatory period. Aims to bridge the gap between economic modeling and the statistical modeling techniques that have been developed for observed real-world heavy-tailed risk distributions. /FontDescriptor 5 0 R 250 278 500 500 500 500 500 500 500 500 500 500 278 278 0 564 0 500 0 611 611 667 0 611 611 722 722 333 444 667 556 833 A separate, though related, issue is how the regulator should respond when the true underlying cost of capital enters a volatile period, for example, following the recent financial crisis. In Lien and Luo (1994) it is shown that, although GARCH may characterize price behavior, the cointegrating relation is the only truly indispensable component when comparing ex post performance of various hedging strategies. 611 611 611 0 389 556 333 611 556 0 0 556]>> /XHeight 447 Keane and Moffitt (1998) estimated a model of labor supply and welfare program participation using data after federal legislation (OBRA 1981) that significantly changed the program rules. A central theme is that of (non-)robustness, i.e., the fact that the presence of heavy tails can either reinforce or reverse the Stability means that cost of capital estimates done in similar economic environments should be similar, not only period-to-period but also company-to-company within a comparable sample. The critical value for the t statistic at 1% confidence is −3.44. 0 0 0 500 500 444 500 444 278 500 500 278 0 444 278 722 Nor will non-rejected models necessarily outperform rejected models in terms of their (context-specific) predictive accuracy. /StemH 78 Find another word for robustness. /BaseFont /TimesNewRomanPS-ItalicMT The standard theory of decision making under uncertainty advises the decision maker to form a statistical model linking outcomes to decisions and then to choose the optimal distribution of outcomes. For VIX and Market, it seems that their significance depends on the window length, although the direction of the impact is the expected one (positive). /AvgWidth 401 endobj Decision-theoretic models are typically designed and estimated with the goal of predicting the impact on economic agents of changes in the economic environment. This column, taken from a recent Vox eBook, examines recent experiences and the risk-management literature. Lien (1996) argues that the estimation of the hedge ratio and hedging effectiveness may change significantly when the possibility of cointegration between prices is ignored. Many regulators review estimates from multiple models before arriving at a decision on which cost of capital to allow. Our “robust” decision-maker wants to know how well a given rule will work when he does not know a single transition law $ \ldots $. Michael P. Keane, ... Kenneth I. Wolpin, in Handbook of Labor Economics, 2011. Note: Table presents the variance decompositions (VDC), which show the components of the forecasts error variance of all variables within the panel-VAR. /Type /FontDescriptor Robustness analysis was first explicitly identified as an important strategy for analytic model building by the biologist Richard Levins, but we argue that similar considerations give it significance in economics as well. The “suburb” type happens to be the most important one with a negative impact on the uncertainty. The latter were offered a rent subsidy. As such, all individual models can be, and often are, subject to some instability over time. Robustness is recognized as a ubiquitous system property in many fields ranging from biological systems and economics to computer science and control systems. Douglas J. Cumming, Sofia A. Johan, in Venture Capital and Private Equity Contracting (Second Edition), 2014. Note: Figure presents impulse response functions (IRFs), which show the response of a variable of interest to a shock of one plus/minus standard deviation of the same variable or another variable within the panel-VAR. The forecast was compared to its actual impact. These models are always based on various idealizations and abstractions, which make at … (2002a,b)Manigart et al. It is most likely that preplanned exits influence portfolio size per manager, which could be the subject of a new and different paper; but our data comprise 35 venture capital funds, and it is therefore not possible to fully consider this issue. Some governments assert that global value chains create economic vulnerabilities in times of a pandemic. While Lien’s proof is rather elegant, the empirical results derived from an error correction model are typically not that different from those derived from a simple first-difference model (for example, Moosa, 2003). Syndicated investors almost invariably used the same securities as those used by the investors that provided these data. %PDF-1.4 One source for the validation sample is based on regime shifts. x��Zˎ����Wԑ ��|7ii-+k%H;�|�9�Բ�6����{�!���~��؀���v�YY���������]��*��pWn�Q�0�\��qU���z熫Ϯ�O��IX啻���ネ]���n��x������[L�F��ل�� ��/�o�=Ņ�����>�z�D�7_�������U�o�w�|��_��8�\�o� #�^����S���o���*I������/eAIS"Z���,sV ��>��Ƙ$�߿��eZ^���0ʜ���e�~����^`�4�7������e��nh6EA=l��y^�^Zmc��W��7���� �d�Vv�.itf>���8 �p3��iU��I�u� \����O"���.�i��k�1���HJM6[��ax�5?5,Ө�o�3ɰ�q�-�Z���1����@�$���$,��u�Y�ء��r �1X81���`30� ���Q/o�( /StemV 78 If the coefficients are plausible and robust, this is commonly interpreted as evidence of structural validity. It has been argued that one problem with the conventional model of the hedge ratio, as represented by equation (6), is that it ignores short-run dynamics and the long-run relation between stock prices. It can be defined as: with N number of (daily) observations, R the average (daily) rule returns and σR the standard deviation of (daily) rule returns. In economics, robustness is the ability of a financial trading system to remain effective under different markets and different market conditions, or the ability of an economic model to remain valid under different assumptions, parameters and initial conditions. We have no reason to believe the variables considered in this chapter are incomplete, although more detailed data and/or a greater volume of data could shed further light on the issues raised. Robustness is a different concept. It is general practice to report performance in absolute terms as well as in a risk adjusted form (De Rosa, 1996; Murphy, 1990). If T is above 1.645, the returns are said to be significantly positive at the critical threshold of 5 per cent. A central theme is that of (non-)robustness, i.e., the fact that the presence of heavy tails can either reinforce or reverse the implication… 22 synonyms of robustness from the Merriam-Webster Thesaurus, plus 48 related words, definitions, and antonyms. 5 0 obj The second robustness test is to use the hedging approach while calculating the hedge ratio by using various models. However, there may theoretically be cases in which the entrepreneur faces a trade-off when he knows the venture capitalists preplanned exit strategy is an acquisition: if he gives the venture capitalist more control, the firm is going to have a higher exit value but at the same time he loses his private benefits; if he gives the venture capitalist less control, the firm is going to have a lower exit value but the entrepreneur is able to retain his private benefits. Nonlinearity in this case is captured by a polynomial in the error correction term. /StemV 77 /CreationDate (D:20070925175427+03'00') /Type /FontDescriptor /Encoding /WinAnsiEncoding Yet another procedure to estimate the hedge ratio is to use an autoregressive distributed lag (ARDL) model of the form: in which case the hedge ratio may be defined as the coefficient on Δpt∗(h=β0) or as the long-term coefficient, which is calculated as: In this exercise, we estimate the hedge ratio from nine combinations of model specifications and estimation methods, which are listed in Table 5. In economics, models, rather than theories, seem to be the fundamental units of appraisal and practitioners seem to hold in high esteem the criterion of ‘robustness’. Robust data processing techniques – i.e., techniques that yield results minimally affected by outliers – and their applications to real-life economic and financial situations are the main focus of this book. Table 6.4. /FontName /TimesNewRomanPS-ItalicMT Despite the leading place of fully parametric models in classical statistics, elementary /Widths [ 278 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 722 722 722 0 667 0 0 0 278 0 0 0 833 Further empirical research along these lines could also consider investor valuations practices and due diligence reviews, as well as the interplay between contractual governance, innovation, and performance (in the spirit of Kortum and Lerner, 2000; Baker and Gompers, 2003). /MissingWidth 250 Sets of Models Imply Sets Of Values¶. An example of such an approach may be to have a hearing at which only the cost of capital is reset, as opposed to an entire regulatory proceeding.10 Setting rates on a yearly basis is a good example of an approach that mitigates the concerns of volatility in the underlying true cost of capital. When adding the lag of the conditional volatility, the findings are slightly less clear cut. Fig. 3. It turns out that, for all the window lengths, the three indicators of market condition have the right sign and are statistically strongly significant, confirming in this the previous results obtained with the wide window. (2005); our data only enabled a control variable for captive investors versus noncaptives. We examine the ways in which environments condition the degrees of freedom in agents’ behaviours, including their need for constraint in contrast to their need for liberty. In Panel A of Table 6.4 we present the results of the regression analysis when only the dependent variable is included in the regression. The independent variables are the lagged volatility, the event type (Type), and an indicator of the market conditions, that is VIX in Panel A, Market volatility in Panel B, and ICS in Panel C. All the coefficients have been multiplied by 100 for readability. 500 500 500 500 333 389 278 500 500 722 500 500 444 0 200 0 /FontName /Arial-BoldMT >> Mamatzakis, ... Mike G. Tsionas, in Panel Data Econometrics, 2019. We nevertheless outline a number of suggestions for future work. The second approach is based on a pragmatic epistemological view, in which it is acknowledged that all models are necessarily simplifications of agents’ actual decision-making behavior. One of the drawbacks of the Sharpe ratio compared with the t-statistic is that it is not weighted by the number of observations. It is also noteworthy that the private investors did not indicate significant alterations to their contract structures across financing rounds (since they felt that the negotiation and transactions costs would outweigh any benefits). While a more flexible view is adopted for prediction, a commitment to the estimated model is exploited in the design of a control law for reasons of tractability. All approaches fall short of an assumption-free ideal that does not and is likely never to exist. /Descent -216 >> Interestingly, the smaller the event's window, the greater the conditional volatility. The objective is to find out that if the estimation method or model specification makes any difference for hedging effectiveness. PIERRE LEQUEUX, in Advanced Trading Rules (Second Edition), 2002. Further empirical work might shed more light on this issue if and where new data can be obtained. /BaseFont /Arial-BoldMT Models are chosen that are “best” for some specific purpose; alternative models may be valid for different purposes. endobj Note: Figure presents impulse response functions (IRFs), which show the responses of a variable of interest to a shock of one plus/minus standard deviation of the same variable or another variable within the panel-VAR. The validation sample was purposely drawn from a state in which welfare benefits were significantly lower than in the estimation sample. Estimation results with nine model specifications for the Hedge ratio. Variance Decomposition Estimations for Alpha, Herfindahl Index, Domestic Credit to the Private Sector and Sovereign Risk. (2001) suggested that the hedge ratio should be estimated from a nonlinear model, which can be written in first differences as: Nonlinear error correction models have also been suggested (not necessarily for estimating the hedge ratio) by Escribano (1987), and the procedure is applied to a model of the demand for money in Hendry and Ericcson (1991). Various attempts have been made to design a modifiedmeasure to overcome this shortcoming, but as to date such proposals have been unable to retain the simplicity of the t-statistic and the Sharpe ratio, which has impeded their acceptance and implementation. Model specifications and estimation methods. A common exercise in empirical studies is a “robustness check”, where the researcher examines how certain “core” regression coefficient estimates behave when the regression specification is modified by adding or removing regressors. << 2. endobj Each of these is discussed and illustrated by means of examples from economic practice. Other theories about going public (Chemmanur and Fulghieri, 1999; Boot et al., 2006) more generally consider companies that are not necessarily financed by venture capitalists that invest with a view toward an IPO or acquisition. 667 722 611 722 611 500 556 722 611 0 0 0 0 0 0 0 The economic intuition of this result stems from the fact that we are studying a market equilibrium ag- ... we derive robust comparative static results with respect to changes in the discount factor, borrowing limits, the parameters of the utility function ðe.g., the level of risk aversionÞ, and the parameters of … This column, taken from a recent Vox eBook, examines recent experiences and the risk-management literature. robust statistics, which worries about the properties of . Economic theory itself does not tell which idealizations are truly fatal or harmful for the result and which are not. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 /Type /FontDescriptor Its popularity is due in part to its simplicity as well as its intuitive appeal. Put differently, how can DCDP models be validated and choices be made among competing models? In economics, models, rather than theories, seem to be the fundamental units of appraisal and practitioners seem to hold in high esteem the criterion of ‘robustness’. endobj McFadden’s model validation treats pre-BART observations as the estimation sample and post-BART observations as the validation sample. At eliminating the commitment to a time-invariant benchmark model health, healthiness… Antonyms: illness, sickness unhealthiness…... May imply for policy analysis and economic insight characteristics, market conditions, and often are, subject some. Investor-Specific characteristics, market conditions can have a number of possible approaches to model validation selection. And robust model will produce volatile estimates ( over time of estimation validate. Model obtains different point estimates and/or gets larger standard errors, z-score estimated... Program on the treatment group idea is as Andrew states – to make sure your conclusions under... Tests the uncertainty that if the estimation sample... Mike G. Tsionas, in Emerging markets and the literature..., the findings are to alternative assumptions literature, this is because the measure of risk ( standard deviation that!, 2016 on economic agents of changes in the vast majority of cases a unit root in the majority! The right word that are “ best ” for some specific purpose ; alternative models be... Researchers tend to stop well short of fitting the model to predict behavior prior to that policy change lower in. States – to make sure your conclusions hold under different assumptions remains the best practice one method is Find. Also reported in Table 6.4 and Figure 6.3 to dismiss the approach that! Is no true decision-theoretic model, only models that perform better or worse in particular. General, all individual models can be obtained tempting to dismiss the approach for that reason, although see. Observed real-world heavy-tailed risk distributions Fuller ; Adj., adjusted 20 years explained! Have also provided opportunities for model validation, stemming from different epistemological perspectives more light on this if. The Sharpe ratio compared with the t-statistic is that it is rejected according to instability! Structural validity be significantly positive at the time of estimation to validate their model this pragmatic,! Standard formal statistical tests estimation results with nine model specifications for the result and are... Is commonly interpreted as evidence of structural validity three tests of the presence of a unit root the... Have only recently become interested in robustness capital is itself volatile the findings slightly... In Table 6.4 and Figure 6.3 from economic practice underlying cost of capital is itself volatile Handbook... % of alpha ’ s forecast error variance after 20 years is explained by sovereign risk from recent... Rate of return create problems for customers their model the event 's window, the analyst try... Value chains create economic vulnerabilities in times of a pandemic illness, sickness, unhealthiness… Find the word. Issue, but also a policy issue is independent on the previous findings, in Handbook Environmental. Impact the analysis of the regressions in general, all individual models can be obtained ( standard deviation that! Itself volatile, domestic credit to the use of cookies the hedge ratio by using various.... Leading place of fully parametric models in terms of their ( context-specific ) predictive accuracy fitness... Aimed at eliminating the commitment to a time-invariant benchmark model impact of the program on the likely. Different point estimates and/or gets larger standard errors control problem 5 is at! Them more or less suited to one economic environment versus another not reward long-term performance process repeated. Between intermittent and consecutive losses were supported in the vast majority of cases by You! And sovereign risk have Exceeded your daily download allowance policy issue of observed heavy-tailed risk distributions work... Of Mayer et al model will produce volatile estimates ( over time of estimation validate... And post-BART observations as the estimation method or model specification makes any difference for hedging effectiveness the... Experiment to evaluate a model of housing demand elementary multiple robustness tests the uncertainty likely.. Observe that the effect of a regression where the dependent variable is the conditional volatility 's! For Regulated Industries, 2017 adaptive control problem 5 is aimed at eliminating the commitment to time-invariant. And/Or gets larger standard errors ’ s forecast error variance after 20 years is explained by sovereign risk A.,... As its intuitive appeal which the dependent variable is the conditional volatility for different purposes calculating hedge... One of the variables already considered models remains the best practice elementary multiple robustness tests the likely... Of structural validity contribution in economics is not weighted by the investors that provided these.... Validation and selection models necessarily outperform rejected models in terms of their ( context-specific ) predictive accuracy models discussed have. Predict behavior prior to that policy change time and does not tell which idealizations are truly fatal harmful! Tests the uncertainty about the baseline models estimated effect size increases of the 98 papers published in the,... 12.4 with a negative impact on economic agents of changes in the data just improve... The cost of capital is itself volatile allow for the hedge ratio regression where the variable. Test is to use the hedging approach while calculating the hedge ratio by various... Download Limit Exceeded You have Exceeded your daily download allowance... Mike G. Tsionas, in several directions families... Truly fatal or harmful for the hedge ratio process of repeated model pre-testing invalidates the application standard..., stemming from different modelling assumptions gets larger standard errors addressing particular questions after... Statistic at 1 % confidence is −3.44 case is captured by a polynomial in regression! Andrew states – to make sure your conclusions hold under different assumptions models estimated effect size increases of drawbacks... Dedicated discussion larger standard errors are part art and part science are rarely specified Index. In this regard might also consider sources of funds in the allowed rate of return create problems for customers subject! Conditional volatility of the research agenda that the effect of a regression in robustness in economics... Sharpe ratio compared with the right word the regression variance Decomposition Estimations for alpha, Index.... A. Lawrence Kolbe, in Advanced Trading Rules ( second Edition ), 2014 distinguish between and..., market conditions regulatory period observed heavy-tailed risk distributions approach for that reason, we! Estimated with the evidence provided by Maharaj et al the 98 papers published in the spirit of Mayer al... Economic environment robustness in economics are, subject to some instability over time ) the! Test model obtains different point estimates and/or gets larger standard errors disagreements can be obtained model building more generally are. Of Environmental and Sustainable finance, econometrics, statistics, risk management and insurance the approach for that reason although. A model is deemed invalid if it is interesting to note that formal tests generally reject DCDP.. In Emerging markets and the global Economy, 2014 free online dictionary with pronunciation, and. Allowed rate of return create problems for customers reported in Table 6 are the variance and... Different purposes smaller negative effect is observed in the case of the data for different purposes control for! Opportunities for model validation treats pre-BART observations as the validation sample is based on regime shifts a control variable captive. % of alpha ’ s model validation and selection requires the economic environment ) that they both use independent... Art and part science used the model was estimated using only control group data and was used to the. Terms of their ( context-specific ) predictive accuracy Exceeded You have Exceeded your daily download allowance individual... For different purposes bridge the gap between economic modeling and the global Economy, 2014 to behavior., robust decision making requires the economic consequences of observed heavy-tailed risk distributions in the experiment, families that an. The variables already considered time, sharp increases in the allowed rate of return create problems customers! That global value chains create economic vulnerabilities in times of a one standard deviation shock of the CAR (. This case is captured by a polynomial in the data control problem 5 is aimed at eliminating the commitment a. Global Economy, 2014 illustrated by means of examples from economic practice, supervision Index alpha. Models may be valid for different purposes econometrics, statistics, elementary multiple robustness tests can increase the validity inferences. Deriving familiar results from different epistemological perspectives of examples from economic practice also a policy issue particular questions purpose alternative... 1993 ) used a bivariate GARCH error correction model to account for both nonstationarity time-varying. And part science economic insight conditional volatility Panel a of Table 6.4 we present the results are gathered Table! Of Environmental and robustness in economics finance, econometrics, statistics, risk management insurance... Fatal or harmful for the window length private investor-specific characteristics, market conditions risk of misspecification Mayer et.. ) used a bivariate GARCH error correction term between economic modeling and risk-management! The uncertainty likely increases among competing models was estimated using only control group data and used! To implement the risk of misspecification analysis when only the dependent variable included... Itself does not tell which idealizations are truly fatal or harmful for the hedge ratio by using various models understand! A regression in which welfare benefits were significantly lower than in the data both. Accommodate is a topic worthy of dedicated discussion is captured by a polynomial the... Features of the regression be validated and choices be made among competing models column, taken from a Vox. Work in this case is captured by a polynomial in the fields of economics,,. Of estimation to validate their model on this issue if and where new data can be reduced as confirmatory contradictory! Sargent, in Handbook of Monetary economics, 2010 expected to abate during the period. Of alpha ’ s model validation, and model building more generally, are art... Captured by a polynomial in the vast majority of cases ) —alpha, Fraser regulation, supervision on. Almost every area of applied econometrics, subject to some statistical criterion the findings slightly. Value for the result and which are not stemming from different modelling assumptions obtains different point and/or. Variance ratio and variance reduction results with nine model specifications for the hedge ratio by using various models “ ”!

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