The mantra when I was an intern learning procedures (drawing an arterial blood gas, placing a subclavian line, etc) was: watch one, do one, teach one. The "one"

The mantra when I was an intern learning procedures (drawing an arterial blood gas, placing a subclavian line, etc) was: watch one, do one, teach one. The "one" part is a little scary, looking back, but the concept is valid.