A Note on the Gains in Accuracy of the Sample Mean with More Data

Forensic economists may base some of their calculations on the average value of a characteristic (e.g., lost earnings of a plaintiff) in a personal injury or wrongful death matter. There is greater precision when using (say) five or six years of data rather than one or two years. However, how much additional accuracy does more data provide? This note provides two tables (based on standard probability/statistical theory) that contain multipliers that forensic economists may want to keep in mind when assessing information gains from more data.