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                                                                    EXHIBIT 31.1

                                  CERTIFICATION


I, Jack Noonan, certify that:

1.       I have reviewed the Annual Report on Form 10-K of SPSS Inc., as amended
         by this Amendment No. 1 to Annual Report on Form 10-K (the "10-K/A");

2.       Based on my knowledge, the annual report, as amended by this 10-K/A,
         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 the annual report, as
         amended by this 10-K/A;

3.       Based on my knowledge, the financial statements, and other financial
         information included in the annual report, as amended by this 10-K/A,
         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 the annual report, as amended by this 10-K/A;

4.       The registrant's other certifying officer(s) and I are responsible for
         establishing and maintaining disclosure controls and procedures (as
         defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the
         registrant and have:

         (a)      Designed such disclosure controls and procedures, or caused
                  such disclosure controls and procedures to be designed under
                  our supervision, to ensure that material information relating
                  to the registrant, including its consolidated subsidiaries, is
                  made known to us by others within those entities, particularly
                  during the period in which the annual report, as amended by
                  this 10-K/A, is being prepared;

         (b)      Evaluated the effectiveness of the registrant's disclosure
                  controls and procedures and presented in the annual report,
                  as amended by this 10-K/A, our conclusions about the
                  effectiveness of the disclosure controls and procedures, as of
                  the end of the period covered by the annual report, as
                  amended by this 10-K/A, based on such evaluation; and

         (c)      Disclosed in the annual report, as amended by this 10-K/A,
                  any change in the registrant's internal control over financial
                  reporting that occurred during the registrant's most recent
                  fiscal quarter (the registrant's fourth fiscal quarter in the
                  case of an annual report) that has materially affected, or is
                  reasonably likely to materially affect, the registrant's
                  internal control over financial reporting; and

5.       The registrant's other certifying officer(s) and I have disclosed,
         based on our most recent evaluation of internal control over financial
         reporting, to the registrant's auditors and the audit committee of the
         registrant's board of directors (or persons performing the equivalent
         functions):

         (a)      All significant deficiencies and material weaknesses in the
                  design or operation of internal control over financial
                  reporting which are reasonably likely to adversely affect the
                  registrant's ability to record, process, summarize and report
                  financial information; and

         (b)      Any fraud, whether or not material, that involves management
                  or other employees who have a significant role in the
                  registrant's internal control over financial reporting.



Date:  August 6, 2004                  By: /s/ Jack Noonan
                                           -------------------------------------
                                           Jack Noonan
                                           President and Chief Executive Officer