Which type of report would include the term "PIR" as a standard measure?

The standard measure referred to by the term "PIR" is the Pilots' Information Report. This type of report is specifically designed to provide vital weather and operational information to pilots. It encompasses information such as current weather conditions, including turbulence, significant weather events, and other factors that are crucial for flight safety and decision-making. Pilots utilize these reports to understand real-time atmospheric conditions and to plan their flights accordingly.

The other options do not align with the established definition of PIR in the context of aviation weather reporting. While "Precipitation Intensity Rate" and "Periodic Information Report" can be relevant in weather reporting, they do not commonly use the acronym PIR in standard practice. "Performance Impact Rating" is also not recognized as a standard measure related to aviation weather reports. Thus, the identification of PIR as the Pilots' Information Report directly correlates with its role in delivering essential data to pilots for enhanced situational awareness.