1. MR. MIM. Riyath DR. A. Jahfer
Exports, Imports, and Economic Growth in Sri Lanka: Evidence from Causality and Co-integration Analysis
MR. MIM. Riyath
DR. A. Jahfer

2. Background
There are many researchers investigated the relationship between Export, Import and Economic growth .

3. Export and Economic growth: Relationship
Export-led growth (ELG),
Growth-driven export (GDE),
Feedback relationship
No relationship.
(Hussain & Saaed, 2014).

4. Studies around the world found:
Unidirectional causality
Bidirectional causality
Could not find any evidence for causality between export and GDP
(Hussain & Saaed, 2014)

5. Research Problem
Studies find that relationships exist between Export, Import and Economic growth in Sri Lankan context.
Velnampy and Achchuthan (2013) find that the export, import and economic growth have the significant positive relationship.
Jahfer and Inoue (2014) find that the trade openness affects economic growth significantly in Sri Lanka.

6. Research Problem cont…
The strong correlation has nothing to say about a relationship between the export, import and the economic development, as it may arise from a purely short-run relationship (Ramos, 2001).
Therefore, the test for existence of a long-run causal relationship among export, import and economic growth is to be performed.
Furthermore, research on the long-run causal relationship between export, import and economic growth is hard to find in Sri Lankan context.

7. Research Question Research Objective
What type of casual relationship exist in long run among the Export, Import and Economic Growth in Sri Lanka?
Research Objective
To find long run causal relationships among the Export, Import and Economic Growth in Sri Lanka.

8. Method and Design
In order to investigate the casual effect among the variables, co-integration test and VECM are applied.
All the data are transferred to natural logarithms.
Unit roots are tested using augmented Dickey-Fuller (ADF) (Dickey & Fuller, 1979) test.
Furthermore, The Phillips-Perron unit root (PP) (Phillips & Perron, 1988) test and Dickey-Fuller (DF) are also performed.

9. Confirm that the variables are integrated of order one.
The co-integration test is done among the variables using the Johansen (1988) co-integration tests.
Since Johansen co-integration is sensitive to the lag length,
Final prediction error (FPE),
Akaike information criterion (AIC),
Schwarz information criterion (SC) and
Hannan-Quinn information criterion (HQ)
are used to determine the appropriate number of lag.
Finally VECM is performed to find long term relationship.

10. Definition of variables
Economic growth is measured using GDP
GDP - the sum of gross value added by all resident producers in the economy.
Exports - the value of all goods and other market services provided to the rest of the world.
Imports - the value of all goods and other market services received from the rest of the world.

11. Sample and Source of data
Sri Lankan economy
Annual data 1962 to 2015 (53 Yeras)
World Development Indicators - World Bank
The GDP, Export and Import data are measured in constant local currency.

12. LgY-GDP LgX-Export LgM-Import
Unit Root Test
series
Levels
1st difference
integrated of order DF
ADF PP
LgY * * *
I(1)
Lag 2
LgX * * *
LgM * *
LgY-GDP LgX-Export LgM-Import

13. VAR Lag Order Selection Criteria
Table 2 VAR Lag Order Selection Criteria
VAR Lag Order Selection Criteria
Endogenous variables: LGY LGX LGM 
Exogenous variables: C 
Sample:
Included observations: 50
 Lag
LogL LR
FPE
AIC SC HQ  
NA    1  
   *
  9.49e-09*
  *
  *
  * 2    
 9.99e-09 3    
 1.06e-08 4    
 1.04e-08
 * indicates lag order selected by the criterion
 LR: sequential modified LR test statistic (each test at 5% level)
 FPE: Final prediction error
 AIC: Akaike information criterion
 SC: Schwarz information criterion
 HQ: Hannan-Quinn information criterion

14. Test for Cointegration
Hypothesized No. of CE(s)
Trace Test
Maximum Eigenvalue Test
Eigenvalue
Trace Statistic
Critical value at 5%
Prob.**
None *
0.0000
0.0001
At most 1
0.0743
0.1291
At most 2
0.1371
 Trace test and Max-eigenvalue test indicates 1 cointegrating eqn(s) at the 0.05 level
 * denotes rejection of the hypothesis at the 0.05 level
 **MacKinnon-Haug-Michelis (1999) p-values

15. Granger-causality in the VECM
To test whether export and import Granger-causes GDP,
∆ 𝐿𝑔𝑌 𝑡 = 𝜆 𝑖=1 𝑛 𝜆 11𝑖 ∆𝐿𝑔𝑌 𝑡−𝑖 + 𝑖=1 𝑛 𝜆 12𝑖 ∆𝐿𝑔𝑋 𝑡−𝑖 + 𝑖=1 𝑛 𝜆 13𝑖 ∆𝐿𝑔𝑀 𝑡−𝑖 + 𝜆 14 𝐸𝐶𝑇 𝑡−𝑙 + 𝜇 𝑡
To test whether GDP and import Granger-causes Export,
∆ 𝐿𝑔𝑋 𝑡 = 𝜆 𝑖=1 𝑛 𝜆 21𝑖 ∆𝐿𝑔𝑋 𝑡−𝑖 + 𝑖=1 𝑛 𝜆 22𝑖 ∆𝐿𝑔𝑌 𝑡−𝑖 + 𝑖=1 𝑛 𝜆 23𝑖 ∆𝐿𝑔𝑀 𝑡−𝑖 + 𝜆 24 𝐸𝐶𝑇 𝑡−𝑙 + 𝜇 𝑡
To test whether GDP and export Granger-causes Import,
∆ 𝐿𝑔𝑀 𝑡 = 𝜆 𝑖=1 𝑛 𝜆 31𝑖 ∆𝐿𝑔𝑀 𝑡−𝑖 + 𝑖=1 𝑛 𝜆 32𝑖 ∆𝐿𝑔𝑌 𝑡−𝑖 + 𝑖=1 𝑛 𝜆 33𝑖 ∆𝐿𝑔𝑋 𝑡−𝑖 + 𝜆 34 𝐸𝐶𝑇 𝑡−𝑙 + 𝜇 𝑡

16. VECM Test results Table 4 Dependent Variable D(LGY) Coefficient
Std. Error
t-Statistic
Prob.
ECT
0.0000*
D(LGY(-1)
0.2286
D(LGX(-1)
0.0168*
D(LGM(-1)
0.0642
D(LGX)
0.1860
0.8572
0.1979
0.4646
D(LGM)
0.7863
0.3531
0.8537
0.8899

17. Conclusion
It finds that the export causes economic growth in the short run and long run.
the import doesn't causes economic growth in the short run
It support the one-way causal relationship between economic growth and export
The result support Export led hypothesis rather than Growth-driven exports in Sri Lankan Economy.