We didn't calculate a hard ROI," says Steve Hansen, VP of corporate information services at Toro Co., of his company's implementation of SAP's human resources, manufacturing, financial, and customer-service applications four years ago. "But we had a bunch of good business reasons for doing it."

Surprisingly, given the level of investment and time needed to implement ERP systems, many companies forged ahead without making ROI calculations. Like Toro, most companies had good reasons for doing so: Some wanted to integrate disparate business units, others wanted to consolidate redundant proprietary systems, and many used ERP systems to help solve their year 2000 problems. Toro, a $1.1 billion maker of lawn mowers and snow throwers in Minneapolis, says its SAP implementation eliminated about 70 homegrown systems that would have required $12 million to $15 million in Y2K remediation work.