<Page>

                                                                    EXHIBIT 31.2

                                  CERTIFICATION

I, J. Phillip Cooper, Executive Vice President and Chief Financial Officer of
Charles River Associates Incorporated, certify that:

     1.   I have reviewed this Amendment No. 2 to the quarterly report on
Form 10-Q of Charles River Associates Incorporated;

     2.   Based on my knowledge, this report does not contain any untrue
statement of a material fact or omit to state a material fact necessary to make
the statements made, in light of the circumstances under which such statements
were made, not misleading with respect to the period covered by this report;

     3.   Based on my knowledge, the financial statements, and other financial
information included in this report, fairly present in all material respects the
financial condition, results of operations and cash flows of the registrant as
of, and for, the periods presented in this report.



Date: July 14, 2004             By:  /s/ J. Phillip Cooper
                                     -----------------------------------------
                                     J. Phillip Cooper
                                     Executive Vice President and
                                     Chief Financial Officer