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Improving early warning indicators for banking crises – satisfying policy requirements
Mathias Drehmann and Mikael Juselius
Bank for International Settlements
“Understanding Macroprudential Regulation”
Norges Bank, Oslo, 29–30 November 2012
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CGFS report No 48
Operationalizing the selection and application of
macroprudential instruments
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Operationalising macroprudential policies
Report focusses on 3 high-level criteria that are key in determining instrument selection and application in practice
The ability to determine the appropriate timing for the activation or deactivation of the instrument
The effectiveness of the MPI in achieving the stated objective
The efficiency of the instrument in terms of a cost- benefit assessment
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Report ends with 9 questions and answers
1. To what extent are vulnerabilities building up or crystallising?
2. How (un)certain is the risk assessment?
3. Is there a robust link between changes in the instrument and the stated policy objective?
4. How are expectations affected?
5. What is the scope for leakages and arbitrage?
6. How quickly and easily can an instrument be implemented?
7. What are the costs of applying a macroprudential instrument?
8. How uncertain are the effects of the policy instrument?
9. What is the optimal mix of tools to address a given vulnerability?
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Report analysis three groups of macroprudential instruments
Capital-based tools (countercyclical capital buffers, sectoral capital requirements and dynamic provisions)
Liquidity-based tools (countercyclical liquidity requirements)
Asset-side tools (loan-to- value (LTV) and debt-to-income (DTI) ratio caps)
For all tools report proposes ‘transmission maps’
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Increase resilience
Impact on the credit cycle
↑ lending spreads
dividend and bonuses
Undertake SEOs1
credit demand
Options to address shortfall
Asset prices
Loan market
Increasecapital requirements or provisions
credit supply
Voluntary buffers
Arbitrage away
Leakages to non-
banks
Expectation channel Reprice
loans
assets, especially with
high RWA
↑ Loss Absorbency
Tighter risk management
Transmission map for capital based tools
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Improving early warning indicators for banking crises – satisfying policy
requirements
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Introduction
CGFS (2012): Policymakers need to be able to determine the appropriate timing for the activation or deactivation of the instrument
In this paper we want to find reliable early warning indicators (EWIs) for systemic banking crises
What policy requirements do EWIs need to satisfy?
Need to be evaluated with preference free methodology
Need to have right timing
Need to be stable
Need to be robust
Need to be understood by policymakers
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We assess a broad range of indicators
We find
Credit-to-GDP gap best indicator for predicting crises 2- 5 years in advance
Debt service ratios highly successful indicator for predicting crises 1-2 years in advance
Implementing the framework
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To fully evaluate quality of a signal would need to know
preferences of policymakers, which are unknown (eg CGFS (2012))
What are costs of acting on wrong signals (false positives)?
What are the benefits of acting on correct signals (true positives)?
→ Need to evaluate signalling quality independent of preferences
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How to evaluate the goodness of an EWI?
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The ROC curve
Policymakers receive noisy signal S
S higher → higher risk of a crisis
At which threshold you policymakers act?
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Area under ROC curve as measure of signalling quality
Area under the ROC curve (AUROC) provides summary measure of the classification ability (eg Jorda and Taylor, 2011):
AUROC=0.5 → uninformative indicator
AUROC=1 → fully informative indicator
AUROC ideal measure if preferences are not known
Benefits
Can be estimated non-paramterically
Has convenient statistical properties
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1
0ROC(FP)dFP AUROC
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Timing of ideal EWIs
Ideal EWI needs to signal crisis early enough
Likely to be 1-2 year lead-lag relationship (e.g.
countercyclical capital buffers)
Policymakers tend to observe trends before reacting (e.g. Bernanke, 2004)
Ideal EWI signal crises not too early
Introducing buffers too early may undermine effectiveness (e.g. Caruana, 2010)
We look at individual quarters within a 5 year horizon
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EWIs need to be stable and robust
Policymakers adjust policy stance gradually
Optimal for MP (Bernanke, 2004, Orphanides, 2003)
Indictor should issue consistent signals
Consistency of signal tied to persistency of underlying series (eg Park and Phillips (2000))
High degree of persistency problematic for statistical inference
Non-parametric approach
EWIs need to be robust to different samples and specifications
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Interpretability of EWI
Evidence that practitioners value sensibility of forecasts more than accuracy (Huss, 1987) adjust forecasts if the lack justifiable explanations (Onka-Atay et al (2009)
Purely statistical approaches are not suitable for policy purposes and communication
Our indicators reflect
excessive leverage and asset price booms (Kindleberger, 2000, and Minsky, 1982)
non-core deposits (Hahm et al, 2012)
the business cycle
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Analysing potential EWIs
We construct and test a range of potential early warning indicators building on Drehmann et al (2011)
We select indicator variables from...
Credit measures: Credit-to-GDP gap and real credit growth
Asset prices: Real property and equity price gaps and real property and equity price growth
None-core bank liabilities (Hahm, Shin, and Shin (2012)):
GDP growth
History of financial crises
...and add one new measure:
Debt service ratio (DSR) (Drehmann and Juselius
(2012)): interest payments and repayments on debt divided by income
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We analyse quarterly time-series data from 27 countries.
The sample starts in 1980 for most countries and series, and at the earliest available date for the rest
Use balanced sample
We follow the dating of systemic banking crises in Laeven and Valencia (2012)
We ignore crises which are driven by cross-boarder exposures
We adjust dating for some crisis after discussions with CBs
Analysing potential EWIs (II)
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Several of the variables display dynamics which are hard to distinguish from I(2) process
Indicators which have performed well in the past are more persistent
→ Benefits of a non-parametric approach
Persistency
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Behaviour around systemic crises
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-5051015
-20 -16 -12 -8 -4 0 4 8 12 DSR
-2002040
-20 -16 -12 -8 -4 0 4 8 12 Credit-to-GDP gap
-40-2002040
-20 -16 -12 -8 -4 0 4 8 12 Property pr. gap
-50050100
-20 -16 -12 -8 -4 0 4 8 12 Equity pr. gap
-10-50510
-20 -16 -12 -8 -4 0 4 8 12 GDP growth
-200204060
-20 -16 -12 -8 -4 0 4 8 12 Non-core deposit ratio
-1001020
-20 -16 -12 -8 -4 0 4 8 12 Credit growth
-2002040
-20 -16 -12 -8 -4 0 4 8 12 Prop. price gr.
-50050100
-20 -16 -12 -8 -4 0 4 8 12 Equity price gr.
0.511.52
-20 -16 -12 -8 -4 0 4 8 12 history
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ROC curves for 2 year forecast horizon
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0.2.4.6.81ROC
0 .2 .4 .6 .8 1
FP DSR
0.2.4.6.81ROC
0 .2 .4 .6 .8 1
FP Credit-to-GDP gap
0.2.4.6.81ROC
0 .2 .4 .6 .8 1
FP Property pr. gap
0.2.4.6.81ROC
0 .2 .4 .6 .8 1
FP Equity pr. gap
0.2.4.6.81ROC
0 .2 .4 .6 .8 1
FP GDP growth
0.2.4.6.81ROC
0 .2 .4 .6 .8 1
FP Non-core deposits ratio
0.2.4.6.81ROC
0 .2 .4 .6 .8 1
FP Credit growth
0.2.4.6.81ROC
0 .2 .4 .6 .8 1
FP Prop. price gr.
0.2.4.6.81ROC
0 .2 .4 .6 .8 1
FP Equity price gr.
0.2.4.6.81ROC
0 .2 .4 .6 .8 1
FP History
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ROC curves over time
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.2.3.4.5.6.7.8.91AUROC
-20 -15 -10 -5 0
Horizon
DSR AUROC .2.3.4.5.6.7.8.91
-20 -15 -10 -5 0
Horizon
Credit-to-GDP gap AUROC .2.3.4.5.6.7.8.91
-20 -15 -10 -5 0
Horizon Property pr. gap
.2.3.4.5.6.7.8.91AUROC
-20 -15 -10 -5 0
Horizon
Equity pr. gap .2
.3.4.5.6.7.8.91AUROC
-20 -15 -10 -5 0
Horizon GDP growth
.2.3.4.5.6.7.8.91AUROC
-20 -15 -10 -5 0
Horizon
Non-core deposits ratio AUROC .2.3.4.5.6.7.8.91
-20 -15 -10 -5 0
Horizon
Credit growth .2
.3.4.5.6.7.8.91AUROC
-20 -15 -10 -5 0
Horizon Prop. price gr.
.2.3.4.5.6.7.8.91AUROC
-20 -15 -10 -5 0
Horizon
Equity price gr. AUROC .2.3.4.5.6.7.8.91
-20 -15 -10 -5 0
Horizon History
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Combining variables
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.2.3.4.5.6.7.8.91AUROC
-20 -15 -10 -5 0
Horizon
Credit/GDP gap Property gap Credit\GDP gap and prop. gap
.2.3.4.5.6.7.8.91AUROC
-20 -15 -10 -5 0
Horizon
Credit/GDP gap DSR Credit\GDP gap and DSR
.2.3.4.5.6.7.8.91AUROC
-20 -15 -10 -5 0
Horizon
DSR Property gap DSR and prop. gap
Credit to GDP gap and
property price gap Credit to GDP gap and DSR
DSR and property price gap
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Robustness checks
Robust across samples
Robust to different crisis dating
Robust to balanced versus unbalanced samples
Robust if partial ROC curves are used
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We argue that EWIs need satisfy six policy requirements:
Need to be evaluated with preferences free methodology
Need to have right timing
Need to be stable
Need to be robust
Need to be understood by policymakers
Appliying this approch to data from 27 countries we find that:
The DSR and the credit-to-GDP gap dominate other EWIs
The DRS dominates at shorter horizons and the credit- to-GDP gap dominates at longer ones
Conclusion
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