It all seems clear in hindsight: The national recession began last March and the state recession in December 2000. The difference in timing reflects the importance of technology production and the stock market to the Massachusetts economy.
Clayton-Matthews, Alan, "Economic Currents: The State of the State Economy" (2002). Public Policy and Public Affairs Faculty Publication Series. 31.
University of Massachusetts
Published in MassBenchmarks, Vol. 5, No. 1, pp. 4-9: http://www.massbenchmarks.org/publications/issues/vol5i1/3.pdf.