Table 1.
Trade volume and unit price effects of VSS coverage, moderated by exporter-importer governance distance and VSS substantive and procedural stringency
| Trade volume effect | Unit price effect | |||||
|---|---|---|---|---|---|---|
| (1) | (2) | (3) | (4) | (5) | (6) | |
| VSSikt-1 | 0.0141*** (0.0025) | 0.0167*** (0.0033) | 0.0127*** (0.0030) | −0.0020*** (0.0004) | −0.0031*** (0.0004) | −0.0027*** (0.0004) |
| VSSikt-1 × | ||||||
| Governance distanceijt | 0.0078*** (0.0019) | 0.0111*** (0.0024) | 0.0062*** (0.0023) | 0.0009*** (0.0003) | 0.0017*** (0.0003) | 0.0011*** (0.0003) |
| Procedural stringencyikt-1 | -0.0057 (0.0037) | 0.0017*** (0.0004) | ||||
| Substantive stringencyikt-1 | −0.0013 (0.0023) | 0.0036*** (0.0003) | ||||
| VSSikt-1 × Governance distanceijt × | ||||||
| Procedural stringencyikt-1 | −0.0073*** (0.0025) | −0.0013*** (0.0002) | ||||
| Substantive stringencyikt-1 | −0.0021 (0.0016) | −0.0015*** (0.0002) | ||||
| Observations | 955,861 | 955,861 | 955,861 | 120,382 | 120,382 | 120,382 |
Notes: Estimated trade volume effect (columns 1 to 3) and unit price effect (columns 4 to 6) moderated by governance distance and by overall substantive and procedural VSS stringency. Estimates derived from augmented gravity models at the exporter(i)-importer(j)-product(k)-time(t) level, estimated using PPML on the full sample (N = 955,861 exporter-importer-product-time trade flow observations) for trade volume effects and the non-zero sample (N = 120,382 exporter-importer-product-time trade flow observations) for unit price effects. All estimations include bilateral, importer-time, exporter-time, and product-time fixed effects. Robust exporter-importer-product standard errors in parentheses. Significance tested with unadjusted two-sided z-test and indicated as ***p < 0.01. Regression results with exact p-values are reported in Supplementary Table S14.
VSS voluntary sustainability standards, PPML Poisson pseudo-maximum likelihood.