Exhibit 99.1
THE ADVISORY BOARD COMPANY
CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002
Each of the undersigned hereby certifies, in his capacity as an officer of The Advisory Board Company (the “Company”), for purposes of 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:
| • | the Annual Report of the Company on Form 10-K for the period ended March 31, 2003 fully complies with the requirements of Section 13(a) of the Securities Exchange Act of 1934; and | ||
| • | the information contained in such report fairly presents, in all material respects, the financial condition and results of operation of the Company. |
| /s/ FRANK J. WILLIAMS | ||
| Frank J. Williams Chief Executive Officer (Principal Executive Officer) and Director | ||
| /s/ DAVID L. FELSENTHAL | ||
| David L. Felsenthal Chief Financial Officer (Principal Financial and Accounting Officer), Secretary and Treasurer |
Dated: June 26, 2003
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