208
Tạp chí
Kinh tế - Kỹ thuật
Year-2014
-0.203
(0.260)
0.832***
(0.279)
Constant
-4.345**
(1.993)
-3.330**
(1.481)
Observations
2,395
2,345
Robust standard errors in perentheses
*p<0.1,**P<0.05,***P<0.01
Table 1 contains descriptive statistics and correlations for the studied variables. Positive
correlations are found between EXPORT and horizontal green product diversification
(HORIZONTAL) and vertical green product diversification (VERTICAL). The results preliminarily
provide support for Hypothesis 2a and Hypothesis 2b. Furthermore, the significant positive
relationship between entrepreneur (ENT) and vertical GPD (VERTICAL) also supports Hypothesis
1b. The significant relationship between FDI and vertical GPD (VERTICAL) provides support for
Hypothesis 3b. Significant evidence has not been found for other hypotheses in the correlation
analysis.
We use two probit regress models to explain firms’ horizontal and vertical GPD. In our regress
model, the observation data for all years are pooled, whilst introducing a dummy variable‘Year’ to
control for differences across years. The industrial heterogeneity is controlled by introducing the
industry dummy variables. The regress results are shown in Table 2.
Table 2 reports the parameter estimates together with levels of significance and robust standard
errors. Both the Probit regress models show that export-oriented firms have a positive effect on the
implementation of horizontal GPD (β=0.278, p<0.1) and vertical GPD (β =0.250, p<0.05). Hence,
Hypothesis 2b is moderately supported and Hypothesis 2a is hardly supported. Entrepreneur and
foreign investors have heterogeneous effects on the implementation of horizontal and vertical GPD.
As shown in Table 2, entrepreneur have a significant effect on vertical GPD (β=0.40, p<0.05).
The result supports Hypothesis 2b. However, its effect on the implementation of vertical GPD is
found not significant (β= -0.04, p>0.1); as the result, Hypothesis 2a is not supported. The effects
of foreign investors on horizontal and vertical GPD are also heterogonous. Compared to domestic
enterprises, foreign-invested enterprises have higher possibility to implement vertical GPD (β
=0.52, p<0.01), and their effect on horizontal GPD is not significant (β = -0.12, p>0.1). This means
that public firms are more sensitive to firms’ environmental impact during the production process.
Contrary to our Hypothesis 4a,b and Hypothesis 5a,b, we have not found any significant evidence
for positive influence of GDPPC and REG on both the horizontal GPD and vertical GPD. The
stringency of regulations has no significant effect on both the horizontal GPD (β= 0.02, p>0.1)
and vertcal GPD green (β = 0.01, p>0.1). Furthermore, the results suggest that GDPPC has no
significant effect on the probability of a firm adopting both horizontal GPD (β = 0.00, p>0.1) and
vertical GPD (β = 0.00, p>0.1).
5. DISCUSSIONS
Internationalization and Environmental Spillovers
The results indicate that the influence of export on both of horizontal and vertical green
product diversification is significant. This supports the hypothesis that international trade improves
the diffusion of green innovation practices, which are consistent with the previous findings that
international trade plays a prominent role in diffusing environment-efficient practices (Albornozet