EXHIBIT 23.9
 
                CONSENT OF NATIONSBANC MONTGOMERY SECURITIES LLC
 
    We hereby consent to the inclusion of our opinion letter dated March 23,
1998 to the Board of Directors of Walsh International Inc. (the "Company")
regarding the acquisition of the Company by Cognizant Corporation in the Proxy
Statement/Prospectus of the Company which is a part of this Registration
Statement on Form S-4 (the "Registration Statement") and to the references
herein to our firm and to our opinion under the heading "The Parties--Opinion of
Financial Advisor to Walsh". In giving the foregoing consent, we do not admit
(i) that we come within the category of persons whose consent is required under
Section 7 of the Securities Act of the 1933, as amended (the "Securities Act"),
or the rules and regulations of the Securities and Exchange Commission
promulgated thereunder, and (ii) that we are experts with respect to any part of
the Registration Statement within the meaning of the term "experts" as used in
the Securities Act and the rules and regulations of the Securities and Exchange
Commission promulgated thereunder.
 
Date: June 1, 1998
 
                                          Very truly yours,
 
                                          NATIONSBANC MONTGOMERY SECURITIES LLC