An Empirical Study on Response to Online Customer Reviews and E-Commerce Sales: From the Mobile Information System Perspective
Table 5
Results of robustness test (sales volume of next month as DV).
SYS-GMM model
Fixed effect of panel data
Model 1
Model 2
Model 3
Model 4
Ratio of response to negative review
0.519 (0.172)
0.419 (0.068)
0.434 (0.077)
0.305 (0.058)
Ratio of response to positive review
0.110 (0.036)
0.097 (0.020)
0.087 (0.022)
0.050 (0.009)
Wald test value ( value)
4.40 (0.000)
4.15 (0.000)
3.98 (0.000)
3.60 (0.000)
Ratio of response to negative review × product price
0.064 (0.020)
0.047 (0.022)
Ratio of response to positive review × product price
0.265 (0.086)
0.210 (0.036)
Ratio of response to negative review × product heterogeneity
0.077 (0.019)
0.125 (0.049)
Ratio of response to positive review × product heterogeneity
0.105 (0.047)
0.129 (0.015)
Other control variable
Included
Included
Included
Included
Wald chi2
5,025.76
8,646.88
Sargan test ( value)
27.503 (0.916)
26.386 (0.939)
AR2 ( value)
1.228 (0.219)
1.311 (0.190)
R2
0.227
0.251
F value
215.91
186.10
Number of observed values
17800
17800
17800
17800
Note. The dependent variable is the sales volume of next month. “∗∗” and “∗∗∗” in the table mean that z-statistics are significant at the levels of 5% and 1%.