The official Poser height translation is 1 Poser unit = 8 feet. In Poser 5 you can see this directly, as it will display in real-world units as well as Poser units. (The first release of Poser 5 had this scale wrong, and I like to think my early and loud complaints helped them to get it right in all subsequent releases.)

See http://www.renderosity.com/messages.ez?Form.ShowMessage=879992

Dr Geep has long and ably argued for his own standard, which does make some kinds of calculations easier, and for which he has posted nice rulers in the Free section.

But his standard makes Vicki nearly 6'2", taller than all but one or two of the tallest supermodels -- a basketball player, really.

This is why I prefer the official standard, which makes Vicki about 5'10". Still considerably taller than average, but not out of line for a fashion model.