The Plan-Do-Study-Act (PDSA) cycle is a systematic series of steps for gaining valuable learning and knowledge for the continual improvement of a product or process. The four stages are:

Plan: Identify an opportunity for improvement and plan a change.

Do: Implement the change on a small scale.

Study: Use data to analyze the results of the change and determine whether it made a difference.

Act: If the change was successful, implement it on a wider scale and continuously assess your results. If the change did not work, begin the cycle again.

In the scenario provided, the team has implemented a new workflow to ensure the correct supplies are available at the start of a procedure. Despite this, a physician reports that key supplies are still missing. This indicates that the change may not have achieved the desired outcome.

The appropriate phase to revisit in this situation is the Study phase. During the Study phase, the team should analyze data and feedback to assess the effectiveness of the implemented change. This involves collecting information on the new workflow's performance, identifying any discrepancies or failures, and understanding why the desired outcome was not achieved. By thoroughly studying the results, the team can gain insights into the shortcomings of the current plan and make informed decisions on necessaryadjustments.

Skipping or inadequately performing the Study phase can lead to the continuation of ineffective processes and prevent the realization of improvement goals. Therefore, revisiting the Study phase is crucial to determine the root causes of the ongoing issue and to inform subsequent actions for improvement.