From the NL Blog:
WHEN: Sunday, April 15th – Saturday, April 21st
Visitors are measured by recording the P number on your gate each hour. Doing so gives us a general idea of what times of the day are busiest at your location. Please check your gate to ensure that it is ready for Door Count.
In-house material use gives us a general idea of print materials that are being used within the library. This count is used by libraries nationally by tallying the number of materials returned to carts each hour. Please make sure you have proper signage to notify your customers.