Overview of the Final Report of the Seattle-Denver Income Maintenance Experiment. The Design and Implementation of SIME/DIME


SIME/DIME was launched in Seattle, Washington, in 1970 and extended in 1972 to a second site in Denver, Colorado.  The prime contractors for SIME/DIME were the States of Washington and Colorado, which subcontracted with SIR International for the design, operation, and research evaluation of the experiment.  SRI International, in turn, subcontracted with Mathematica Policy Research (MPR) for the administration of the cash transfer or negative income tax (NIT) treatment and all the field data collection from both experimental and control groups.  For the administration of the job counseling/training subsidy treatment, SRI subcontracted with the Seattle Central Community College and the Community College of Denver.

The experiment involved almost 5,000 families.  In order to test whether, and if so to what extent, behavioral responses varied by duration of treatment, the families in the experimental groups were also randomly assigned to a 3-year or 5-year treatment duration.  The four basic treatment combinations were

  1. NIT only,
  2. Counseling/training only,
  3. NIT and counseling/training,
  4. no treatment.

The NIT and counseling treatments are described briefly below.