* Campus culture and enforcement: Campuses with strong environmental programs, clear anti-littering policies, and visible enforcement tend to have lower littering rates.
* Campus size and design: Larger campuses with less visible waste receptacles or inadequate waste management systems may see higher rates.
* Student body demographics and attitudes: The environmental awareness and personal habits of the student population significantly impact littering behavior.
* Time of year: Littering might increase during peak seasons or events.
* Method of data collection: Studies using self-reporting might underrepresent littering, while direct observation studies might be more accurate but more resource-intensive.
Therefore, any percentage would be a rough estimate and not generalizable. While studies might exist for specific campuses, a global average is impossible to determine reliably.