Except as otherwise provided by law, each commodity board established under the supervision and oversight of the Secretary of Agriculture pursuant to a commodity promotion law shall, not less often than every 5 years, authorize and fund, from funds otherwise available to the board, an independent evaluation of the effectiveness of the generic commodity promotion programs and other programs conducted by the board pursuant to a commodity promotion law. The board shall submit to the Secretary, and make available to the public, the results of each periodic independent evaluation conducted under this subsection.