Reference: Boydstun, J. (1975). The San Diego field interrogation experiment. Washington, DC: Police Foundation.

Strategy: Proactive arrests-zero tolerance arrests

Matrix Dimensions:
X-axis: Communities/neighborhoods
Y-axis: General
Z-axis: Proactive

Results: Statistically significant success
More field interrogations associated with fewer outdoor crimes

Methodological Rigor: Moderate- weak comparison group

Abstract (from NCJRS): Field interrogation (FI) as used by the San Diego Police Department is a contact initiated by a patrol officer who stops, questions, and sometimes searches a person because he has reason to suspect that the subject may have committed, may be committing, or may be about to commit a crime. Each police officer is given extensive training in recognizing valid FI situations and in conducting interrogations. The effectiveness of the Department's FI program in combating crime on the streets was evaluated. Chosen for comparison were three patrol areas, which were matched on demographic and socio-economic composition and prior reported crime histories a Control area, where FI activities were conducted with no change from normally practiced activities; a Special FI area, where interrogations were conducted only by officers who were given special supplemental FI training; and a No-FI area, where interrogations were suspended entirely for the nine-month study period. The study evaluated the effects of FI policies on (1) reported crimes considered suppressible (potentially subject to reduction through police patrol activities), (2) total arrest rates, and (3) police-community relations. Community attitude surveys were conducted in each of the three areas before and after the experimental period. Some level of FI activity, as opposed to none, provides a deterrent effect on suppressible crimes in localized areas. The suspension of field interrogations in the No-FI area was associated in time with a significant increase in the monthly frequency of total suppressible crimes. The resumption of interrogations in this area was associated in time with a significant decrease in this same crime rate. Monthly means of suppressible crimes went from 75, before the experiment, to 104, when interrogations were suspended, and back to 81 when they were resumed. The monthly frequencies of total suppressible crimes did not change significantly in either the Control or Special FI areas. Specific types of suppressible crimes most influenced by the level of FI activity were not identified. Suppressible crimes tend to decline one month after FI activities are increased. The monthly frequencies of total arrests in all study areas were not significantly influenced by the levels of FI activities. However, patrol officers attribute 17 per cent of their total arrests to contacts that began as field interrogations. The quality of arrests resulting from FI contacts is slightly lower than for arrests in other circumstances. In regard to race, age, and sex there were no significant differences between the subjects of field interrogations in the Control area and subjects of arrests made by Special FI officers. However, the Control group arrested significantly more blacks and significantly fewer Mexican Americans than they field-interrogated. There were no indications of race e discrimination through unjustified arrests by either Control or Special groups. Changes in type and frequency of FI activities did not have a major effect on police-community relations in any of the areas. The majority of citizens accepted such activity as legitimate police procedure and felt that an appropriate amount of police time is devoted to the practice. The majority of all citizens who were subjected to FI contacts felt that the contact was justified and properly conducted. Only 3 per cent of all complaints department-wide were related to FI activity. Subjects reacted more favorably to interrogations conducted by Special FI officers than to those conducted by Control officers. More than 98 per cent of field interrogations reported do not result in arrests.