Both Uses of

Dutch
in
Outliers

In the 1960s and 1970s, the Dutch psychologist Geert Hofstede was working for the human resources department of IBM's European headquarters.†
Chpt 7 *

In 1974,1 actually saw the Dutch (low PDI) prime minister, Joop den Uyl, on vacation with his motor home at a camping site in Portugal.†
Chpt 7

Definitions:

(1) (Dutch)
the people of the Netherlands (including Holland); or relating to them (including the name of their language)

Many people refer to the Netherlands as Holland -- which is more accurately the most populous region of the Netherlands. The Netherlands is best known for having 25% of its land below sea level.
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Less commonly, Dutch is used in a the phrase Dutch oven (a thick-walled cooking pot with a tight-fitting lid) or Dutch doors (a door divided in such a fashion that the bottom half may remain shut while the top half opens).