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                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C.  20549



                                  SCHEDULE 13G



                   Under the Securities Exchange Act of 1934

                              (Amendment No. 2)*


                        PIA MERCHANDISING SERVICES, INC.
                                (Name of Issuer)


                                  COMMON STOCK
                         (Title of Class of Securities)


                                   693360109
                                 (CUSIP Number)


Check the following box if a fee is being paid with this statement [ ].  (A
fee is not required only if the filing person:  (1) has a previous statement on
file reporting beneficial ownership of more than five percent of the class of
securities described in Item 1; and (2) has filed no amendment subsequent
thereto reporting beneficial ownership of five percent or less of such class.)
(See Rule 13d-7).

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).



                               Page 1 of 5 pages

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- -----------------------                                  ---------------------
  CUSIP NO.  693360109              13G                    PAGE 2 OF 5 PAGES
- -----------------------                                  ---------------------
 
- ------------------------------------------------------------------------------
      NAME OF REPORTING PERSON
 1    S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
                                                                                
      HEARTLAND ADVISORS, INC.
                                                 
      #39-1078128         
- ------------------------------------------------------------------------------
      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
2                                                               (a) [ ]
                                                                (b) [ ]
                                                 
- ------------------------------------------------------------------------------
      SEC USE ONLY
 3
      

- ------------------------------------------------------------------------------
      CITIZENSHIP OR PLACE OF ORGANIZATION
 4                                 
      WISCONSIN, U.S.A.

- ------------------------------------------------------------------------------
                          SOLE VOTING POWER
                     5                                                       
     NUMBER OF            
                          999,200
      SHARES       -----------------------------------------------------------
                          SHARED VOTING POWER
   BENEFICIALLY      6       
                          None 
     OWNED BY
                   -----------------------------------------------------------
       EACH               SOLE DISPOSITIVE POWER
                     7       
    REPORTING             
                          1,124,200
      PERSON       -----------------------------------------------------------
                          SHARED DISPOSITIVE POWER
       WITH          8       
                          None 
- ------------------------------------------------------------------------------
      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
 9                           
         1,124,200
- ------------------------------------------------------------------------------
      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
10           

 
- ------------------------------------------------------------------------------
      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
11           
      20.8%                                                              

- ------------------------------------------------------------------------------
      TYPE OF REPORTING PERSON*
12           
      IA

- ------------------------------------------------------------------------------

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CUSIP NUMBER  693360109                    Page 3 Of 5 Pages

Item 1.
    (a) Name of Issuer:  PIA Merchandising Services, Inc.
        --------------                                   


    (b) Address of Issuer's Principal Executive Offices:
        ----------------------------------------------- 
         19900 MacArthur Blvd., Suite 900
         Irvine,  CA   92612

Item 2.
    (a) Name of Person Filing:  Heartland Advisors, Inc.
        ---------------------                             
 

    (b) Address of Principal Business Office:
        ------------------------------------ 
             Heartland Advisors, Inc.
             790 North Milwaukee Street
             Milwaukee, WI  53202

 
    (c) Citizenship:  Heartland Advisors is a Wisconsin corporation.
        -----------                                                      
 
    (d) Title of Class of Securities:  Common Stock
        ----------------------------               

    (e)  CUSIP Number: 693360109
         ------------           

Item 3. If this statement is filed pursuant to Rule 13d-1(b),
        -----------------------------------------------------
        or 13d-2(b), check whether the person filing is a:
        --------------------------------------------------

  (a)_____    Broker or Dealer registered under Section 15 of
              the Act.

  (b)_____    Bank as defined in Section 3(a)(6) of
              the Act.

  (c)_____    Insurance company as defined in Section 3(a)(19)
              of the Act.

  (d)_____    Investment company registered under Section 8 of
              the Investment Company Act of 1940.

  (e)  X      Investment adviser registered under Section 203 of
     -----    the Investment Advisers Act of 1940.

  (f)_____    Employee Benefit Plan, Pension Fund which is subject
              to the provisions of the Employee Retirement
              Income Security Act of 1974 or Endowment Fund;  see
              Sec 240.13d-1(b)(1)(ii)(F).

<PAGE>
 
  (g)_____     Parent Holding Company, in accordance with
               Sec 240.13d-1(b)(ii)(G) (Note:  See Item 1).

  (h)_____     Group, in accordance with
               Sec 240.13d-1(b)(1)(ii)(H).

Item 4. Ownership.
        --------- 

    (a) Amount beneficially owned:
        --------------------------
        1,124,200 shares may be deemed beneficially owned within the meaning of
Rule 13d-3 of the Securities Exchange Act of 1934 by Heartland Advisors, Inc.

    (b) Percent of Class:
        ---------------- 
        20.8%

    (c)  For information on voting and dispositive power with respect to the
above listed shares, see Items 5-8 of the Cover Page.

Item 5. Ownership of Five Percent or Less of a Class.
        -------------------------------------------- 

        If this statement is being filed to report the fact that as of the date
hereof the reporting person has ceased to be the beneficial owner of more than
five percent of the class of securities, check the following:[ ]

Item 6. Ownership of more than Five Percent on Behalf of Another
        --------------------------------------------------------
        Person.
        ------ 

        The shares of common stock to which this Schedule relates are held in
investment advisory accounts of Heartland Advisors, Inc. As a result, various
persons have the right to receive or the power to direct the receipt of
dividends from, or the proceeds from the sale of, the securities. The interests
of one such account, Heartland Value Fund, a series of Heartland Group, Inc., a
registered investment company, relates to more than 5% of the class.

Item 7. Identification and Classification of the Subsidiary Which Acquired the
Security Being Reported on By the Parent Holding Company.

      Not Applicable.

Item 8. Identification and Classification of Members of the Group.
        --------------------------------------------------------- 

      Not Applicable.

Item 9. Notice of Dissolution of Group.
        ------------------------------ 

      Not Applicable.

<PAGE>
 
Item 10.  Certification.
          ------------- 

     By signing below, I certify that, to the best of my knowledge and belief,
the securities referred to above were acquired in the ordinary course of
business and were not acquired for the purpose of and do not have the effect of
changing or influencing the control of the issuer of such securities and were
not acquired in connection with or as a participant in any transaction having
such purposes or effect.

                                   SIGNATURE

     After reasonable 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.

DATE: February 2, 1998

                      HEARTLAND ADVISORS, INC.
    
                      By:  PATRICK J. RETZER
                           Patrick J. Retzer
                           Senior Vice President/Treasurer