Noreen Mavro-Flanders, Dukes County treasurer and also chairman of the Cape Cod Municipal Health Group (CCMHG) board of directors, wrote this week to explain that the description of that organization as a “purchasing group,” in the article “Martha’s Vineyard towns to trim health care costs” needs clarification.

“CCMHG does not ‘buy’ health insurance,” Ms. Mavro-Flanders wrote. “We are self-insured. Therefore, the CCMHG Board sets the rates for the plans offered. Harvard Pilgrim Health Care, Blue Cross Blue Shield of Massachusetts and Tufts Health Plans only administer our claims on a per-member basis.”