Which sign depicts periods where processes are stalled?

The sign that depicts periods where processes are stalled is represented by the Waiting Time sign. This concept is essential in Lean IT as it highlights the inefficiencies that occur when tasks or processes are not actively progressing due to delays. These stalls often result from various factors like resource unavailability, dependencies on other tasks, or bottlenecks in the workflow.

In Lean principles, minimizing waiting times is crucial because they do not add value to the product or service and can lead to increased lead times and reduced overall efficiency. Understanding and identifying waiting times allows organizations to optimize their processes, streamline operations, and ultimately enhance customer satisfaction by delivering products or services more promptly.

The other signs mentioned refer to different types of inefficiencies or waste. Over-processing indicates work being done beyond what is necessary. The transport of goods sign pertains to unnecessary movement of materials or products, which also can introduce inefficiencies. The defects or rework sign highlights issues resulting from errors that require additional effort to correct. While all these signs are important in Lean practices, the Waiting Time sign specifically identifies stalled processes, making it the correct choice for this question.