For its fourth annual ranking of the world's largest publicly held manufacturing companies, IndustryWeek has partnered with Waltham, Mass.-based Primark, an information-services company that collects, integrates, and delivers financial, economic, and market-research information to financial, corporate, and government decision-makers. Primark's global databases are maintained by its Financial Information Div. and were used to identify all publicly held manufacturing companies with annual revenues of $1.0 billion or more. The actual cutoff for inclusion in the IW 1000 was $1.63 billion. Through its network of 80 offices in 61 countries, Primark obtained the latest available financial data on these companies. This process was further facilitated through the division's research service and Worldscope product, and supplemented with Internet-based research. Erik L. Fine, an information consultant, compiled the data. Manufacturing companies were defined according to criteria established by IW. Those criteria included: companies with a majority of their business in a manufacturing industry; computer software companies whose primary business is the manufacture of software programs; oil and gas companies that derive approximately 50% or more of their revenues from the refining of oil and gas products; and companies that derive approximately 50% or more of their revenues from the manufacture of mined materials. Because all publicly held manufacturing companies were eligible, a number of subsidiary or associated companies that are publicly traded separately from their parent company made the list along with the parent. The data elements are based on information obtained directly from publications issued by the corporations. Revenue numbers do not include items considered as "other income." Currency valuations in U.S. dollars were made using rates as of Dec. 31, 1998. Where 1998 data are not available, 1997 data are given. An asterisk next to the company name on the IW 1000 list indicates that 1997 data were used. Where 1997 figures are given, profit growth is for 1996-97. A not-meaningful code was used for the return on equity and debt-to-equity ratios when equity was negative. In instances where companies showed negative net income for the comparative year, an "NM" appears in the profit-growth column. An "NA" appears in cases where data were not available. Readers should keep in mind that accounting standards and terminology vary from country to country. Direct comparisons of figures, even when terms appear to be the same, can be misleading.