How To Evaluate an Early Warning System ? Towards a unified Statistical Framework for Assessing Financial Crises Forecasting Methods Early Warning System (EWS) Evaluation Toolbox ========================================================================== INPUT: - observed crises series for a certain country (1 - crisis; 0 - calm) - probability sequence (obtained from any type of EWS model) OPTIONAL: a second probability sequence and the option nested=1 % 1 if the 2 models are nested (m2 nestes m1 !!!) -------------------------------------------------------------------------OUTPUT: 1. For each model (series of probabilities) Identification fo the optimal cut-off - Optimal cutoff (sensitivity-specificity criteria) - Confusion matrix for this optimal cut-off - Optimal cutoff (accuracy measures - Younden index) - Confusion matrix for this optimal cut-off - Optimal cutoff (misclassification error measures-Total error) - Confusion matrix for this optimal cut-off Evaluation criteria: -QPS; -LPS; -AUC; -Pietra Index; Plots: - Sensitivity-Specificity - Accuracy and Misclassification Error Measures - ROC curve - Crisis Probabilities vs. Observed Crises 2. Comparison Tests (only if 2 series of probabilities are specified) Clark-West and ROC tests: ( test-statistic and p-value) H0: the 2 models have equal forecasting abilities H1: the models have different forecasting abilities (identify the higher AUC (res. the lower QPS) to find the outperforming model) Results for model 1 -----------------------------------------------------------------------------I) Optimal cut-off Identification ===================================================== a. Sensitivity-Specificity criteria ----------------------------------------------------- page 1 cut-off = 0.091 Observed: no crisis 0.956 crisis Predicted: no crisis crisis 0.044 0.077 0.923 b. Accuracy Measures - Younden Index ----------------------------------------------------cut-off = 0.069 Observed: no crisis 0.956 crisis Predicted: no crisis crisis 0.044 0.000 1.000 c. Misclassification Error Measures - Total Error ----------------------------------------------------cut-off = 0.069 Observed: no crisis 0.956 crisis Predicted: no crisis crisis 0.044 0.000 1.000 II) Evaluation criteria ===================================================== QPS 0.038 LPS 0.059 AUC 0.989 Pietra 0.338 ===================================================== Results for model 2 -----------------------------------------------------------------------------I) Optimal cut-off Identification ===================================================== a. Sensitivity-Specificity criteria ----------------------------------------------------cut-off = 0.241 page 2 Observed: no crisis 0.956 crisis Predicted: no crisis crisis 0.044 0.077 0.923 b. Accuracy Measures - Younden Index ----------------------------------------------------cut-off = 0.219 Observed: no crisis 0.956 crisis Predicted: no crisis crisis 0.044 0.000 1.000 c. Misclassification Error Measures - Total Error ----------------------------------------------------cut-off = 0.219 Observed: no crisis 0.956 crisis Predicted: no crisis crisis 0.044 0.000 1.000 II) Evaluation criteria ===================================================== QPS 0.081 LPS 0.209 AUC 0.988 Pietra 0.338 ===================================================== Results for the comparison tests -----------------------------------------------------------------------------II) Comparison tests ===================================================== ROC Clark-West Test statistic 0.842 0.252 P-value 0.359 0.801 ===================================================== page 3 Sensitivity−Specificity Plot Crisis Probability vs. Observed crisis 1 1 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4 0.4 0.3 0.3 0.2 0.2 0.1 0.1 0 0 50 100 150 Time Observed Crisis 200 250 Optimal cut−off 300 0 0 0.1 0.2 0.3 0.4 0.5 Cut−off Sensitivity EWS 0.6 0.7 0.8 0.9 1 0.9 1 Specificity Accuracy and Misclassification Error Measures Plot 1 Receiving Operating Characteristic (ROC) Curve 1 0.9 0.9 0.8 0.8 0.7 0.7 0.6 Sensitivity 0.6 0.5 0.4 0.5 0.4 0.3 0.3 0.2 0.2 0.1 0.1 0 0 0.1 0.2 0.3 Younden index 0.4 0.5 Cut−off MCC 0.6 Total error 0.7 0.8 Weighted error 0.9 1 0 0 0.1 0.2 0.3 0.4 0.5 0.6 1−Specificity EWS page 4 Random model 0.7 0.8 Sensitivity−Specificity Plot Crisis Probability vs. Observed crisis 1 1 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4 0.4 0.3 0.3 0.2 0.2 0.1 0.1 0 0 50 100 150 Time Observed Crisis 200 250 Optimal cut−off 300 0 0 0.1 0.2 0.3 0.4 0.5 Cut−off Sensitivity EWS 0.6 0.7 0.8 0.9 1 0.9 1 Specificity Accuracy and Misclassification Error Measures Plot 1 Receiving Operating Characteristic (ROC) Curve 1 0.9 0.9 0.8 0.8 0.7 0.7 0.6 Sensitivity 0.6 0.5 0.4 0.5 0.4 0.3 0.3 0.2 0.2 0.1 0.1 0 0 0.1 0.2 0.3 Younden index 0.4 0.5 Cut−off MCC 0.6 Total error 0.7 0.8 Weighted error 0.9 1 0 0 0.1 0.2 0.3 0.4 0.5 0.6 1−Specificity EWS page 5 Random model 0.7 0.8 CODER INFORMATION Bertrand Candelon Maastricht University Elena-Ivona Dumitrescu University of Orleans Christophe Hurlin University of Orleans PLEASE CITE THE PUBLICATION AND THE COMPANION SITE Candelon, B., Dumitrescu, E. and Hurlin, C. (2012), ”How To Evaluate an Early Warning System ? Towards a unified Statistical Framework for Assessing Financial Crises Forecasting Methods” , IMF Economic Review Candelon B., Dumitrescu E. and Hurlin C. (2012), ”How To Evaluate an Early Warning System ? Towards a unified Statistical Framework for Assessing Financial Crises Forecasting Methods”. RunShare Companion Website www.runshare.org/CompanionSite/Site70 Powered by Matlab page 6
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