What is the most common clue left by subjects in a search?

Footprints are the most common clue left by subjects in a search because they provide direct evidence of where a person has walked or traveled. Footprints can indicate not only the direction of travel but also can help to establish the time frame of the activity based on environmental conditions such as weather, terrain, and the condition of the footprints themselves. Analyzing footprints allows searchers to track the subject's movements, assess their physical state (such as if they were running or walking), and even discern if there is a chance that they may have encountered obstacles or made course changes.

While other clues like trash, pieces of gear, and broken branches can also provide valuable information, they are often more sporadic and less reliable than footprints. Trash may only indicate where the subject stopped for a break, broken branches could be caused by various factors not related to the subject, and pieces of gear could have different meanings depending on the context of their location. In contrast, footprints are generally more consistent indicators of movement and can lead searchers closer to the subject's current location.