In the study of American population it is necessary to distinguish two separate scientific concepts:
(1) The American of Polish origin,
(2) The Polish-American (Polono-Amerykanin)
Individuals of the first category — Americans of “Polish blood” — make up the Polish “Statistical Group.” This group is represented, but only partly and with a high coefficient of error, in the pertinent section of the American census.
Individuals of the second category, which includes the great majority of Americans of Polish origin, are not represented as such in any official statistics. They comprise the Polish “Sociological Group.“ This is the group that calls itself in Polish Polonia.