American trade policy towards Sub Saharan Africa –- a meta analysis of AGOA

Test(s) of heterogeneity:

Heterogeneity
statistic

degrees of
freedom

P

I-squared**

Tau-squared

Seyoum(2007)

44.03

13

0.000

70.5%

0.0854

Giovannetti and Sanfilippo (2009)

11.98

21

0.940

0.0%

0.0000

Nouve (2005)

8.57

15

0.899

0.0%

0.0000

Collier and Venables (2007)

0.48

8

1.000

0.0%

0.0000

Lederman and Ozden (2007)

83.66

4

0.000

95.2%

2.4182

Nouve and Staatz (2003)

101.14

17

0.000

83.2%

0.0023

Frazer and Van Biesebreock (2008)

0.05

3

0.997

0.0%

0.0000

Cooke (2011)

16665.22

19

0.000

99.9%

0.2560

Cooke (2009)

20.75

19

0.351

8.4%

0.0011

Tadesse and Fayissa (2010)

102.28

31

0.000

69.7%

0.0072

Tadesse, et al (2008)

6.12

12

0.910

0.0%

0.0000

Overall

1.2e+05

172

0.000

99.9%

0.0572

Overall Test for heterogeneity between sub-groups:
_________________________ I 1.0e+05

10

0.000

Significance test(s) of ES=0

Seyoum (2007)

z= 0.48

p = 0.632

Giovannetti and Sanfilippo (2009)

z= 8.70

p = 0.000

Nouve (2005)

z= 21.51

p = 0.000

Collier and Venables (2008)

z= 1.58

p = 0.114

Lederman and Ozden (2007)

z= 1.51

p = 0.131

Nouve and Staatz (2003)

z= 3.60

p = 0.000

Frazer and Van Biesebreock (2010)

z= 0.17

p = 0.865

Cooke(2011)

z= 4.17

p = 0.000

Cooke(2009)

z= 1.55

p = 0.121

Tadesse and Fayissa (2008)

z= 1.14

p = 0.252

Tadesse, et al (2008)

z= 0.59

p = 0.558

Overall

z= 4.97

p = 0.000