Measuring Lambda Through Self‐reports*

The Rand Corporation 's pioneering study on self‐reported measures of individual offending rates has generated considerable controversy. In this study, the Rand methodology was refined in an attempt to achieve more precise estimates of λ Individual interviews, a more detailed calendar system, and month‐by‐month reporting were used with an intake cohort of 403 recently convicted male offenders. This paper examines variability in offending rates within individuals, in particular their highest rates and most recent rates, and the implications for measuring λ