Jack Welch led a massive restructuring and transformation of GE during his tenure from 1981 to 2001. He sold off underperforming businesses, cut costs aggressively through layoffs and restructuring, and instilled a culture of results and continuous improvement. Welch focused GE on becoming #1 or #2 in global markets, developing a strategy of pursuing the best practices of top competitors. He emphasized developing world-class talent through his "four E's" philosophy. Welch's relentless focus on performance and efficiency drove tremendous growth and profitability for GE, though some critiques argue it may have come at the cost of other priorities like customer service and quality. Overall, Welch played a transformative and hugely important role in GE's