This study develops the Decision-Process Bottlenecks (DPB) Scale, a stage-based instrument that advances organizational research by theoretically integrating cognitive, structural, and coordination constraints into a unified process construct. Moving beyond traditional decision-making literature, the DPB framework operationalizes latent disruptions across information gathering, sensemaking, deciding, and implementing. Validated through a multi-stage mixed-methods approach with U.S. managers, the resulting 28-item scale demonstrates robust psychometric properties and high structural integrity. Nomological tests using the NASA Task Load Index reveal that these bottlenecks significantly escalate perceived workload and impair decision effectiveness under pressure. By providing a granular diagnostic for decision-cycle friction, this research offers a novel theoretical lens to analyze how organizational constraints manifest as measurable process failures. Practically, the scale enables targeted interventions to enhance decision tempo and execution consistency.