Exhibit 6

November 10, 1998
 
The Board of Directors
Concentra Corporation
21 North Avenue
Burlington, MA 01803-3301
 
Members of the Board:
 
  You have requested our opinion (the "Opinion") as to the fairness, from a
financial point of view, to the shareholders of Concentra Corporation
("Concentra" or the "Company") of the consideration to be received by such
shareholders pursuant to the Agreement and Plan of Merger (the "Agreement"),
dated November 10, 1998, by and among Concentra, Oracle Corporation ("Oracle")
and a wholly-owned subsidiary of Oracle (the "Purchaser").
 
  The Agreement provides, in general, that the Purchaser will make a tender
offer (the "Offer") for all of the outstanding shares of Common Stock of
Concentra and the associated Series A Participating Cumulative Preferred Stock
purchase rights at a price per share of $7.00 (the "Acquisition Price") net to
the seller in cash. The obligation of the Purchaser to pay for the shares
tendered will be subject to, among others things, there being tendered such
number of shares as will, when added to any shares already owned by the
Purchaser or Oracle, constitute at least 51% of the shares of Concentra,
determined on a fully diluted basis. The Agreement further provides that, as
soon as practicable after the completion of the Offer, the Purchaser will be
merged into Concentra (the "Merger", and collectively with the Offer, the
"Acquisition") and each share of Common Stock of Concentra and the associated
purchase rights will be converted into the right to receive in cash an amount
equal to the highest price paid per share in the Offer.
 
  The Agreement further provides that each holder of a Concentra stock option
will receive a cash payment equal to the excess of (a) the Acquisition Price
times the number of shares of Concentra Common Stock subject to such option
that is vested and exercisable (including those options that become vested and
exercisable as a result of the transaction) over (b) the aggregate exercise
price of such option.
 
  It is our understanding that the parties intend that the transaction will be
accounted for as a purchase for financial reporting purposes.
 
  For the purposes of rendering the Opinion, we have, among other things:
 
 
  (i)  reviewed a copy of the executed Agreement;
 
  (ii) discussed the terms of the Agreement with Concentra management and the
       Concentra Board of Directors;
 
  (iii) interviewed management of Concentra concerning the business prospects,
        financial outlook and operating plans of the Company;
 
  (iv)  reviewed certain historical and certain projected financial statements
        and other relevant financial and operating data of Concentra prepared
        by the management of the Company;
 
  (v)  assessed, in consultation with our associates in the Corporate Finance
       department of Volpe Brown Whelan & Company, LLC ("VBW&Co."), the
       positioning of the Acquisition, in an effort to evaluate Concentra's
       alternatives and strategic options and the potential market reaction to
       the Acquisition and the potential likelihood that the shareholders of
       Concentra would accept the Offer;

 
  (vi) reviewed the valuation of selected publicly-traded companies we deemed
       relevant for the valuation analysis;
 
  (vii) reviewed the historical stock trading patterns of Concentra and
        analyzed the premium of the Acquisition Price in relation to
        historical Concentra stock trading ranges;
 
  (viii)  reviewed premiums paid in comparable merger and acquisition
          transactions and merger and acquisition transaction generally in
          relation to the premium represented by the Acquisition Price at
          different times prior to the date of announcement;
 
  (ix) reviewed, to the extent publicly available, the financial terms of
       selected merger and acquisition transactions that we deemed relevant
       for the valuation analysis;
 
  (x)  performed a discounted cash flow analysis of the SellingPoint business
       and the ICAD cash flow stream based upon financial projections of
       Concentra management;
 
  (xi) performed a maximum price payable for no dilution valuation based on
       the maximum non-dilutive price payable under purchase accounting
       conventions;
 
  (xii) performed a valuation analysis of LoanData based on a discount to the
        valuation established by the last investment round made in LoanData;
        and
 
  (xiii) performed such other studies, analyses and inquiries and considered
         such other information as we deemed relevant.
 
  VBW&Co. relied without independent verification upon the accuracy and
completeness of all of the financial, accounting, legal, tax, operating and
other information provided to VBW&Co. by Concentra and has relied upon the
assurances of Concentra that all such information is complete and accurate in
all material respects and that there is no additional material information
known to it that would make any of the information made available to VBW&Co.
either incomplete or misleading.
 
  Concentra has also retained outside legal, accounting, and tax advisors to
advise on matters relating to the Acquisition. Accordingly, VBW&Co. has
assumed the accuracy of such advice for purposes of its opinion and has not
independently verified or confirmed such advice and expresses no opinion on
such matters.
 
  Although Concentra had discussions with third parties concerning possible
business combinations, for purposes of this opinion we were not requested to
consider, and we are expressing no opinion as to, the relative merits of the
Acquisition as compared to any other business combination or alternative
business strategies that might exist for Concentra or the effect of any other
business combination in which Concentra might engage.
 
  With respect to the projected financial data of Concentra and its component
businesses, all of which has been provided by the management of Concentra,
VBW&Co. has relied upon assurances of Concentra that such data has been
prepared in good faith on a reasonable basis reflecting the best currently
available estimates and judgments of Concentra management as to the future
financial performance of Concentra and its component businesses. Our Opinion
is based, in large part, on these projected financial data and estimates.
 
  VBW&Co. is relying upon the information provided to it by Concentra for the
purposes of rendering the Opinion. VBW&Co. expresses no opinion and has made
no investigation with respect to the validity, accuracy or completeness of the
information provided to it and does not warrant any projections included in
such information. Actual results that Concentra might achieve in the future
may vary materially from those used in VBW&Co.'s analysis.
 

 
  VBW&Co. has assumed that the Acquisition will be consummated in accordance
with the terms of the Agreement and that no subsequent material changes or
amendments will be made prior to completion of the Acquisition. Any material
changes could impact the VBW&Co. analysis and Opinion. VBW&Co. has,
furthermore, not made any independent appraisals or valuations of any assets
of Concentra or any of its component businesses, nor has VBW&Co. been
furnished with any such appraisals or valuations. VBW&Co. has performed no
investigations relating to the representations and warranties made by
Concentra, Oracle or the Purchaser, including representations with respect to
intellectual property rights and status of any litigation pending or
threatened against any company. While VBW&Co. believes that its review, as
described herein, is an adequate basis for the Opinion, the Opinion is
necessarily based upon market, economic and other conditions that exist and
can be evaluated as of the date of the Opinion, and any change in such
conditions would require a re-evaluation of the Opinion.
 
  The Opinion addresses only the fairness, from a financial point of view, of
the Acquisition Price to Concentra and does not address the relative merits of
the Acquisition and any alternatives to the Acquisition, Concentra's decision
to proceed with or the effect of the Acquisition, or any other aspect of the
Acquisition.
 
  The preparation of a fairness opinion involves various judgments as to
appropriate and relevant quantitative and qualitative methods of financial
analyses and the application of those methods to the particular circumstances
and, therefore, such an opinion is not readily susceptible to summary
description. Accordingly, we believe our analyses and the factors utilized in
such analysis must be considered as a whole and that considering any portion
of such analyses or factors, without considering all analyses and factors
could create a misleading or incomplete view of the process underlying the
Opinion. In our analyses, we made numerous assumptions with respect to
industry performance, general business and other conditions and matters, many
of which are beyond Concentra's control and are not susceptible to accurate
prediction.
 
  No opinion is expressed herein as to the future trading price or range of
prices of any securities of Concentra issued prior to the Acquisition.
Furthermore, the Opinion does not constitute a recommendation as to the Board
of Director's decision on whether to support the Acquisition and recommend it
to Concentra's shareholders and does not constitute a recommendation to
shareholders as to whether to tender their shares in the Offer or vote in
favor of the merger. The Opinion and related materials have been prepared for
the use and benefit of the Board of Directors of Concentra and may not be used
for any other purpose, except that this opinion may be included in any filing
which Concentra makes with the Securities and Exchange Commission with respect
to, and distributed to the shareholders of Concentra in connection with, the
Acquisition. Although developments following the date of the Opinion may
affect the Opinion, VBW&Co. assumes no obligation to update, revise or
reaffirm the Opinion.
 
  As a customary part of its investment banking business, VBW&Co. engages in
the valuation of businesses and their securities in connection with mergers
and acquisitions, negotiated underwritings, secondary distributions of
securities, private placements and valuations for corporate and other
purposes. In the ordinary course of its business, VBW&Co. and its affiliates
may actively trade the equity securities of Concentra or Oracle and its
affiliates for their own account and for the accounts of customers and,
accordingly, may at any time hold a long or short position in such securities.
 
  VBW&Co. will receive a fee for rendering its Opinion, no portion of which is
conditioned upon the Opinion being favorable. In addition, VBW&Co. is to be
paid a fee upon the close of any combination transaction.
 
  Based upon and subject to the foregoing limitations and restrictions and
after considering such other matters as we deem relevant, it is our opinion
that, as of the date hereof, the Acquisition Price is fair, from a financial
point of view, to the shareholders of Concentra.
 
Very truly yours,
 
VOLPE BROWN WHELAN & COMPANY, LLC
 
By: /s/ Steve Piper
  -------------------------
Steve Piper
Compliance Officer