Measuring Marketing Efficiency Under Risk: Evidence From Türkiye's Wheat Sector Using Risk‐Adjusted Marketing Efficiency Index and Bayesian Structural Time Series

ABSTRACT This study analyzes the processes by which producers in Türkiye's wheat market evaluate their products through different marketing channels using a multilayered approach. The Risk‐Adjusted Marketing Efficiency Index (R‐MEI), developed to overcome the limitations of the classic Marketing Efficiency Index (MEI), integrates risk factors such as price volatility and market uncertainty, enabling a more realistic assessment of farmers' decisions. This study also examines the effects of external shocks on marketing efficiency, such as the COVID‐19 pandemic, Russia–Ukraine war, and the 2023 Kahramanmaraş earthquake, using the Bayesian Structural Time Series (BSTS) model. Data were collected from producers, institutions, and market actors representing five key marketing channels: traders, commodity exchanges, licensed warehousing, cooperatives, and the Grain Board (GB). The findings show that GB and cooperatives are the most advantageous channels for farmers in terms of efficiency and risk management, while the trader channel stands out as the most fragile structure due to high costs and uncertainty. Although commodity exchanges and licensed warehouses offer relatively higher gross prices to producers, they generate limited net benefits for farmers because of transaction costs and volatility. This research comprehensively reveals not only the technical and economic dimensions of marketing efficiency, but also risk sensitivity, resilience to external shocks, and the relationship between producer behavior and the institutional context. In this respect, it provides policymakers with a concrete roadmap for developing transparent, data‐driven, and long‐term strategies for the Turkish wheat market.