Abstract
We conduct a 2x2 factorial field experiment with a leading Chinese apparel brand and 155 of its suppliers to study how governance structure shapes supplier compliance with multi-dimensional reporting mandates. We independently vary decision authority (mandate versus delegation of KPI selection) and monitoring scope (comprehensive versus targeted carbon audit). Contrary to classical organizational theory, simpler governance structures generate substantially higher engagement among capacity-constrained small and medium-sized enterprises. Mandating a fixed KPI set reduces the missing-data rate by 10.4 percentage points relative to the control mean, while delegating KPI choice yields a negligible effect. Targeted carbon audits raise documentation coverage by 0.857 additional categories, roughly four times the effect of comprehensive audits. The two interventions are mutually reinforcing, with gains concentrated among smaller suppliers and in environmental reporting, where measurement standards are clearer and coordination costs are lower. We develop a model of bandwidth-constrained compliance that rationalizes these patterns and draw implications for the private regulation of externalities in global value chains.