Zacks Earnings Large Cap US Index aims to generally track the performance of the largest 1000 stocks in the U.S., while striving to outperform the comparable universe on both a market-capitalization weighted and equally weighted basis. In its effort to deliver outperformance, Zacks relies upon two proprietary investment factors - Zacks Rank and Zacks Quality. The Zacks Rank factor focuses on Earnings Estimate Revision information, while the Zacks Quality factor focuses on Earnings Quality information.