When “average boarding time” hides the night trolley queue

Monthly boarding averages are a favourite slide in Thai private hospitals. They compress hundreds of trolley hours into a single number that often sits under a target line. Meanwhile the night charge nurse can name the specialties that clog the corridor after 22:00.

What the average erases

Boarding that clusters between midnight and 05:00 disappears inside a 24-hour mean. So does boarding that hits only two destination wards. When we rebuild the same extract as a distribution by daypart and destination, leadership usually stops debating whether a problem “exists” and starts arguing about which ward opens first.

A workable briefing habit

Bring three charts, not twelve: daypart distribution, destination ward share of long waits, and a small timeline sample of cases over a threshold you agree in advance (for example four hours). Ask the room to mark which chart surprises them. The surprise is the agenda.

Data caution

Agree what timestamp means “bed ready” before you plot. Cleaning start and nurse acceptance are not interchangeable, and mixing them invents a false improvement when housekeeping stamps earlier.