During which phase of PDCA is the plan implemented on a large scale after successful results?

The phase of PDCA, which stands for Plan-Do-Check-Act, where the plan is implemented on a large scale after successful results is the Act phase. During the Act phase, if the results from the Check phase show that the plan is effective and meets the objectives, the process or plan moves into broader implementation. This means making necessary adjustments based on feedback and establishing procedures or practices that are proven to be successful to ensure sustained improvements.

The Act phase emphasizes formalizing the changes, ensuring that they are integrated into the organization’s standard operating procedures, and communicating them to all relevant stakeholders. This part of the PDCA cycle is crucial for institutionalizing the lessons learned and ensuring continuous improvement in the organization's processes.