This study synthesizes what is known about time-to-impact in quality improvement (QI) and transformation initiatives and, drawing on a large body of High Performance Organization (HPO) transformation cases, identifies which factors delay or accelerate impact and which organizational practices shorten benefit lead-times. It combines a structured synthesis of academic studies addressing impact, time-to-impact, timing evidence, and associated factors/practices with a case-survey of 54 documented HPO transformation cases that were systematically coded using a common framework. Factors and practices are prioritized based on their recurrence across cases, after which the resulting empirical patterns are mapped back to literature-based categories to assess convergence and divergence. Across the HPO cases, the most recurrent sources of delay are weak change communication and dialogue, weak follow-up and accountability, inconsistent leadership attention, and limited transparency in performance measurement and reporting. The most recurrent accelerators are strong communication and knowledge sharing, a tight review cadence with closed feedback loops, transparent measurement and reporting, and cross-unit collaboration. The most frequently reported time-to-impact reduction practices include institutionalizing a recurring communication-and-review cadence, increasing measurement transparency, clarifying leadership roles and accountabilities, and creating structured dialogue channels supported by internal coaches or champions. Overall, the findings overlap substantially with the literature, but differ in emphasis, and the study positions time-to-impact as a distinct dimension of improvement effectiveness while offering an evidence-informed, prioritized set of practical levers grounded in both research and cross-case practice.