Choose the movement that answers the question
For a storefront, you may need passersby and entries. For an event, you may need arrivals at a gate or movement through a hall. Write the question first so observers do not silently switch between different definitions.
Assign one boundary to each observer
Use a doorway, gate, corridor line, or pavement marker as the boundary. If a building has several entrances, treat them as separate observation points and combine them only after confirming that the time windows match.
Separate passersby, entries, and exits
Someone walking past a building is not an entry. Someone leaving may or may not belong in the same metric as an arrival. Use mutually exclusive buttons or separate rounds so each total keeps a clear meaning.
Use fixed time windows
Fifteen-minute rounds make setup changes and observer fatigue easier to manage. At an event, repeat before opening, during arrival peaks, between sessions, and at departure rather than averaging unlike periods together.
Split high-volume flows before they become uncountable
For wide gates or dense crowds, divide the boundary into visible lanes and assign one observer to each lane. Record any temporary closure, queue, or obstruction that changes how people cross.
Keep the result tied to its context
Label every round with the entrance, date, exact time, event phase, weather, and unusual conditions. The goal is not one impressive total but a set of observations that another person can understand and repeat.