WASHINGTON, D.C. 20549


                                   SCHEDULE TO
                                 (RULE 14D-100)

                             TENDER OFFER STATEMENT
                UNDER SECTION 14(d)(1) OR SECTION 13(e)(1) OF THE
                        SECURITIES EXCHANGE ACT OF 1934
                                (AMENDMENT NO. 3)

                          GIGA INFORMATION GROUP, INC.
                      (Name Of Subject Company (Issuer))

                            FORRESTER RESEARCH, INC.
                           WHITCOMB ACQUISITION CORP.
                      (Names of Filing Persons (Offerors))

                    COMMON STOCK, PAR VALUE $0.001 PER SHARE
                         (Title of Class of Securities)

                      (CUSIP Number of Class of Securities)


                               Tim Moynihan, Esq.
                            Forrester Research, Inc.
                              400 Technology Square
                               Cambridge, MA 02139
                            Telephone: (617) 613-6000
                     (Name, address and telephone number of
                    person authorized to receive notices and
                   communications on behalf of filing persons)


                                   COPIES TO:

                             Keith F. Higgins, Esq.
                               Ann L. Milner, Esq.
                                  Ropes & Gray
                             One International Place
                           Boston, Massachusetts 02110
                            Telephone: (617) 951-7000

                            CALCULATION OF FILING FEE

    Transaction Valuation*                           Amount Of Filing Fee**
- --------------------------------------------------------------------------------
          $60,000,000                                         $5,520

*     Estimated solely for purposes of calculating amount of filing fee in
      accordance with Rule 0-11(d) under the Securities Exchange Act of 1934, as
      amended (the "Exchange Act"). The calculation of the transaction valuation
      is based on 14,064,000 shares of common stock of Giga Information Group,
      Inc. ("Giga") at a purchase price of $4.75 per share. Such number includes
      all outstanding shares as of January 20, 2003, and assumes the exercise of
      all in-the-money stock options and warrants to purchase common stock of
      Giga which are exercisable in connection with the transaction.

**    Previously paid.

[ ]   Check the box if any part of the fee is offset as provided by Rule
      0-11(a)(2) and identify the filing with which the offsetting fee was
      previously paid. Identify the previous filing by registration statement
      number or the Form or Schedule and the date of its filing.

Amount Previously Paid:                                                     N/A
Form or Registration No.:                                                   N/A
Filing Party:                                                               N/A
Date Filed:                                                                 N/A

[ ]   Check the box if the filing relates to preliminary communications made
      before the commencement of a tender offer. Check the appropriate boxes
      below to designate any transactions to which the statement relates:
[X]   third-party tender offer subject to Rule 14d-1.
[ ]   issuer tender offer subject to Rule 13e-4.
[ ]   going-private transaction subject to Rule 13e-3.
[ ]   amendment to Schedule 13D under Rule 13d-2.

      Check the following box if the filing is a final amendment reporting the
      results of the tender offer: [ ]


      This Amendment No. 3 amends and supplements the Tender Offer Statement on
Schedule TO (the "Schedule TO") filed with the Securities and Exchange
Commission on January 27, 2003 and amended on January 28, 2003 and February 13,
2003 by Forrester Research, Inc., a Delaware corporation ("Parent"), and
Whitcomb Acquisition Corp., a Delaware corporation and a wholly owned subsidiary
of Parent (the "Purchaser"). The Schedule TO relates to the offer by the
Purchaser to purchase all the outstanding shares of common stock, $0.001 par
value per share (the "Shares"), of Giga Information Group, Inc., a Delaware
corporation (the "Company"), together with the associated rights to purchase
Series A Junior Preferred Stock, par value $0.001 per share, issued pursuant to
the Rights Agreement dated as of February 18, 2000 between the Company and
American Stock Transfer & Trust Co., at a purchase price of $4.75 per Share, net
to the seller in cash, less any required withholding taxes and without interest
thereon, upon the terms and subject to the conditions set forth in the related
offer to purchase dated January 27, 2003 (the "Offer to Purchase"), and in the
related letter of transmittal. Capitalized terms used and not otherwise defined
herein have the meanings assigned thereto in the Schedule TO.


      Items 1 through 9 and 11 of the Schedule TO which incorporate by reference
the information contained in the Offer to Purchase are hereby amended as

      1.    The last paragraph in the section of the Offer to Purchase entitled
            "Acceptance for Payment and Payment" beginning on page 13 of the
            Offer to Purchase is hereby amended and restated to read in its
            entirety as follows:

            "The Purchaser reserves the right to transfer or assign, in whole or
            from time to time in part, to Parent, or to one or more direct or
            indirect wholly owned subsidiaries of Parent, the right to purchase
            Shares tendered pursuant to the Offer, but any such transfer or
            assignment will not relieve the Purchaser of its obligations under
            the Offer and will in no way prejudice the rights of tendering
            stockholders to receive payment for Shares validly tendered and
            accepted for payment pursuant to the Offer. If the Purchaser
            transfers or assigns the right to purchase the Shares tendered
            pursuant to the Offer, Parent and the Purchaser will amend the
            Schedule TO that they have filed with the Commission and, if
            required by the applicable rules and regulations of the Commission,
            extend the Offer."

      2.    The second paragraph in the section of the Offer to Purchase
            entitled "Contacts and Transactions with the Company; Background of
            the Offer" beginning on page 18 of the Offer to Purchase is hereby
            amended and restated to read in its entirety as follows:

            "In mid-December 2002, Mr. Colony approached Mr. Weiler to discuss
            the possibility of Parent acquiring the Company. During a meeting on
            December 19, 2002 between Mr. Weiler and Mr. Colony, Mr. Weiler
            offered that an acquisition of the Company in the $2 to $4 range did
            not make sense but that further discussions would make sense at a
            higher price."


      After due inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

                                      WHITCOMB ACQUISITION CORP.

                                      By:  /s/ Tim Moynihan
                                            Name:  Tim Moynihan
                                            Title: President

                                      FORRESTER RESEARCH, INC.

                                      By:  /s/ Warren Hadley
                                            Name:  Warren Hadley
                                            Title: Chief Financial Officer

Dated:  February 19, 2003