Most of the recent enrollment growth at large health carriers came from plan administration arrangements.

Researchers at Mark Farrah Associates, Kennebunk, Maine, have published that finding in an analysis of membership data released by 8 large carriers in the second quarter of 2007 and the second quarter of 2008.

Overall enrollment grew 6.1%, but the number of fully insured health plan members increased just 1%, the Farrah researchers report.

Enrollment in “self-funded” plans grew about 11%, the researchers found.

The number of individuals in the 8 carriers’ “administrative services only” plans grew 6.9 million, the researchers estimate.