Estimator and System Variables in Eyewitness Identification

A distinction between estimator and system variables is made in the eyewitness research literature between two categories or types of variables that influence the accuracy of eyewitness accounts. System variables are those that are (or can be) under the control of the justice system, whereas estimator variables cannot be controlled by the justice system. Examples of system variables include factors such as the instructions given to eyewitnesses prior to their viewing a lineup or the number of people who are used in a lineup. Examples of estimator variables include factors such as how good a view the eyewitness had of the perpetrator during the crime or whether the witness and perpetrator were of the same or different race. The estimator versus system variable distinction tends ...