Screening or constraining? The relationship between participation and target achievement in transboundary air pollution treaties

Enforcement and management scholars alike expect that countries participating in an international agreement will more likely achieve predetermined targets than nonparticipating countries will. The management school ascribes this expected association to a constraining effect of the treaty; the enforcement school ascribes it to a screening effect. If the latter conjecture is correct, the association between participation and target achievement should significantly weaken (or even vanish) when controlling for targets' ambition level and other confounding factors. We test this hypothesis on a new dataset comprising three protocols under the Convention on Long-Range Transboundary Air Pollution (CLRTAP). Our results suggest that the positive association between participation and target achievement is robust to controlling for confounding factors; hence, our data suggests that these CLRTAP protocols have indeed constrained participating states.