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                                                                   Exhibit 99.1




DRAFT 3/23/98 10 a.m.
FINAL REVIEWS/APPROVALS BY NOON 3/23/1998

                                                                            NEWS
Cognizant

Contact: Joseph C. Allen                                  FOR IMMEDIATE RELEASE
           (203) 222-4235

                IMS HEALTH SIGNS DEFINITIVE AGREEMENTS TO ACQUIRE
                          WALSH INTERNATIONAL AND PMSI

            COGNIZANT CORPORATION SPIN-OFF STRENGTHENS ITS LEADERSHIP
                       IN THE HEALTH INFORMATION INDUSTRY

Westport, CT, Mar. 23, 1998 - Cognizant Corporation (NYSE:CZT), Walsh
International Inc. (NASDAQ:WSHI) and Pharmaceutical Marketing Services Inc.
(NASDAQ:PMRX) today announced the signing of definitive agreements for IMS
HEALTH to acquire Walsh and PMSI. IMS HEALTH is the premier global provider of
information solutions to the pharmaceutical and healthcare industries, with more
than $1 billion in 1997 revenue.

         "The acquisition of Walsh and PMSI consolidated IMS HEALTH's leadership
position in our core markets," said Robert E. Weissman, Cognizant chairman and
chief executive officer. "Customer value is enhanced by offering broader global
coverage, an expanded product and service portfolio, and accelerated investments
in innovative new products. Financially, these transactions are accretive
near-term beginning in 1999, adding growth businesses which result in improved
shareholder value."

         Under terms of the agreements, Walsh shareholders will receive .3041
shares of Cognizant common stock per Walsh share, as payment to shareholders of
$167 million, and

                                       
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PMSI shareholders will receive .2800 shares of Cognizant common stock per PMSI
share, as payment to shareholders of $180 million. The number of Cognizant
shares received is subject to a collar adjustment based on the price of
Cognizant shares during a period prior to the closing of the transactions. Walsh
currently has approximately 10.6 million shares outstanding; PMSI shares
outstanding total approximately 12.4 million.

         The transactions have been independently authorized by the Cognizant,
Walsh and PMSI boards of directors, and are subject to approval by Walsh and
PMSI shareholders. The transactions will be accounted for under purchase
accounting and are projected to close in the second quarter of 1998, subject to
regulatory approval. Both transactions are expected to be tax-free.

         Walsh International, based in Newtown, PA, generated revenue of $54
million in its fiscal year ended June 30, 1997, and employs approximately 500
professionals in 14 countries. Walsh, established in 1988, develops and markets
leading-edge sales force automation systems for pharmaceutical companies. The
company's integrated technology, data and services are used by 540
pharmaceutical sales forces in 85 healthcare companies in over 30 countries
around the world. Precise(TM) and Premiere(TM), two of Walsh's leading
electronic territory management systems (ETMS) products, today support over
14,000 users.

         New York-based PMSI had ongoing information services revenue of $74
million for its fiscal year ended June 30, 1997, and employs approximately 500
professionals in nine countries. PMSI was established in 1991 and provides a
range of information services to pharmaceutical and healthcare companies in the
U.S., Europe and Japan. On Dec. 15, 1997, PMSI completed the acquisition of
Source Europe, a business delivering prescription database services in five
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European countries. Scott-Levin, PMSI's U.S. subsidiary, provides market
research and managed care audits, as well as strategic consulting, to
pharmaceutical companies in the U.S. PMSI is the international leader in
physician profiling database services, with its Scriptrac(TM) service offered in
Europe and Japan.

         "IMS HEALTH is committed to building customer value," said Victoria R.
Fash, IMS HEALTH president and chief operating officer. "Walsh and PMSI together
complete a global product portfolio of IMS sales and marketing services. We plan
to accelerate investment in innovative new business solutions, including
physician micro-marketing, and the integration of ETMS mobile technology with
IMS databases. By offering full-spectrum global solutions, IMS HEALTH enables
improved efficiency and effectiveness, designed to increase productivity for our
pharmaceutical customers worldwide, said Ms. Fash.

         In Europe, IMS HEALTH plans to accelerate its prescription database
launch significantly by combining the IMS Xtrend(TM) and PMSI's Source(TM)
micro-marketer initiatives. Walsh's Pharbase(TM) data and PMSI's physician
profiles enable enhanced physician targeting services. Scott-Levin will
strengthen IMS HEALTH's market research business in the U.S. by adding new
capabilities in market research audits, managed care services and consulting
services.

         The combination of IMS HEALTH's Sales Technologies, which is focused
primarily in the U.S., and Walsh, concentrated in Europe and Asia Pacific,
instantly creates the global leader in ETMS for pharmaceutical companies
worldwide. Combined, Sales Technologies and Walsh support over 35,000 users.

         "Financially, these acquisitions are sound investments," said Ms. Fash.
"Both are projected to be earnings neutral in 1998, becoming accretive in 1999.
Cost synergies in known 
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areas, such as duplicate data supply contracts, are the key assumption driving
1999 accretion. Walsh International and Scott-Levin offer attractive revenue
growth rates, anticipated in the mid-teens range near-term. While we believe
long-term revenue upside exists, incremental revenue has not been incorporated
in the projections, based on a conservative financial approach."

         IMS HEALTH is the world's leading provider of information solutions to
the pharmaceutical and healthcare industries. Pharmaceutical sales, prescription
and market data and analysis are offered, along with decision support systems
that facilitate the advancement of world health. IMS HEALTH operates in more
than 90 countries, and its businesses include: IMS, the leading global provider
of sales management and market research information to pharmaceutical companies;
Erisco, a provider of software-based administrative and analytical solutions to
the healthcare industry; Cognizant Technology Solutions, an outsourcer of
software applications and development services; and Enterprises, the company's
venture capital unit, focused on investments in emerging healthcare businesses.
IMS HEALTH is also the largest shareholder of GartnerGroup (NASDAQ:GART), the
premier provider of research and advisory services to the information technology
industry.

         IMS HEALTH is currently a unit of Cognizant Corporation (NYSE:CZT). On
Jan. 15, 1998, Cognizant announced plans to become two independent public
companies by mid-1998: IMS HEALTH and Nielsen Media Research. Additional
information is available at Cognizant's Website: http//www.cognizantcorp.com

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Mar. 23, 1998
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This press release includes statements which may constitute forward-looking
statements made pursuant to the safe harbor provisions of the Private Securities
Litigation Reform Act of 1995. Although Cognizant believes the expectations
contained in such forward-looking statements are reasonable, it can give no
assurance that such expectations will prove correct. This information may
involve risks and uncertainties that could cause actual results of Cognizant,
IMS HEALTH, Walsh International or PMSI to differ materially from the
forward-looking statements. Factors which could cause or contribute to such
differences include, but are not limited to (i) the risks associated with
operating on a global basis, including fluctuations in the value of foreign
currencies relative to the U.S. dollar, and the ability to successfully hedge
such risks, (ii) the ability to develop new or advanced technologies and systems
for their businesses on a cost-effective basis, (iii) the ability to
successfully achieve estimated effective tax rates and corporate overhead
levels, (iv) regulatory and legislative initiatives, particularly in the area of
medical privacy, (v) deterioration in economic conditions, particularly in the
pharmaceutical, healthcare, information technology or other industries in which
their customers operate, (vi) conditions in the securities markets which may
affect the value or liquidity of portfolio investments, and (vii) other factors
detailed in Cognizant's SEC filings.