POWER OF ATTORNEY

1.	Appointment

	BY THIS POWER OF ATTORNEY,
I, the undersigned Marc D. Nelson of SPSS Inc., a Delaware Corporation (the
"Company"), HEREBY APPOINT DR. EDWARD HAMBURG, EXECUTIVE VICE PRESIDENT,
CORPORATE OPERATIONS, CHIEF FINANCIAL OFFICER AND SECRETARY OF THE COMPANY,
MR. ANTHONY CIRO, VICE PRESIDENT, LEGAL COUNSEL OF THE COMPANY AND MR.
ROBERT BRINKMANN, ASSISTANT SECRETARY, TREASURER AND CONTROLLER OF THE
COMPANY, AT 233 SOUTH WACKER DRIVE, 11TH FLOOR, CHICAGO, ILLINOIS 60606, to
be my Attorney and in my name and on my behalf and as my Attorney do any
act and deed or otherwise to negotiate, determine and approve the final
form and content of, complete, sign, execute, exchange and deliver any and
all agreements, documents, letters, forms, instruments of transfer,
consents, and other documents, and to do any and all acts and things as may
be necessary or, in the opinion of my Attorney, desirable or incidental
thereto in connection with or for the purposes of executing documents in
connection with the requirements of Section 16(a) of the Securities
Exchange Act of 1934 and the rules and regulations promulgated thereunder
(the "Section 16 Reporting Requirements").

2.	Intention and
Ratification

	I HEREBY UNDERTAKE to ratify and confirm all acts and
things done or lawfully caused to be done and all agreements, documents,
letters, forms, instruments of transfer, consents and other documents,
approved, completed, signed, executed and delivered whatsoever by my
Attorney in my name and on my behalf in pursuance of the authority
conferred in this Power of Attorney and I accept full responsibility for
the contents of the documents referred to above which may be approved,
completed, signed, executed and delivered by my Attorney in my name and on
my behalf.

3.	Indemnity

	I FURTHER UNDERTAKE to indemnify and
keep indemnified my Attorney from and against all losses, liabilities,
costs, claims, actions, expenses, proceedings and obligations incurred or
suffered by my Attorney by reason directly or indirectly of the exercise or
purported exercise of any power conferred upon him or her.

4.	Duration


	I HEREBY DECLARE that the authority conferred by this Power of
Attorney shall be effective as of the date hereof and shall continue in
effect for so long as I am required to file statements with the Securities
and Exchange Commission in connection with the Section 16 Reporting
Requirements with respect to the Company's securities (the "Duration
Period").  Notwithstanding the foregoing, I may, by a written instrument,
signed, acknowledged and delivered to my Attorney during the Duration
Period, with a copy to the Company's Secretary, revoke this Power of
Attorney in whole or in part or amend it from time to time in any respect.


IN WITNESS WHEREOF, I have executed and delivered this Power of
Attorney this 18th day of May, 2004.

Name:  /s/ Marc D. Nelson


Specimen signature of Attorney-in-Fact


/s/ Edward Hamburg


/s/ Anthony Ciro

/s/ Robert Brinkmann



STATE OF Illinois )

			SS.
COUNTY OF Cook )

The undersigned, a notary public in and
for the above county and state, certifies that Marc D. Nelson has caused
this Power of Attorney to be executed and is known to me to be the same
person whose name is subscribed above, appeared before me in person and
acknowledged signing and delivering the instrument as his free and
voluntary act, for the uses and purposes therein set forth, and certified
to the correctness of the signature of the Attorney-in-Fact.

Dated:
May 18, 2004

/s/ Barbara L. Lips
Notary Public


My commission
expires:
November 9, 2007