This data collection was undertaken to gather information on the extent of police officers' knowledge of search and seizure law, an issue with important consequences for law enforcement. A specially-produced videotape depicting line duty situations that uniformed police officers frequently encounter was viewed by 478 line uniformed police officers from 52 randomly-selected cities in which search and seizure laws were determined to be no more restrictive than applicable United States Supreme Court decisions. Testing of the police officers occurred in all regions as established by the Federal Bureau of Investigation, except for the Pacific region (California, Oregon, and Washington), since search and seizure laws in these states are, in some instances, more restrictive than United States Supreme Court decisions. No testing occurred in cities with populations under 10,000 because of budget limitations. Fourteen questions to which the officers responded were presented in the videotape. Each police officer also completed a questionnaire that included questions on demographics, training, and work experience, covering their age, sex, race, shift worked, years of police experience, education, training on search and seizure law, effectiveness of various types of training instructors and methods, how easily they could obtain advice about search and seizure questions they encountered, and court outcomes of search and seizure cases in which they were involved. Police department representatives completed a separate questionnaire providing department characteristics and information on search and seizure training and procedures, such as the number of sworn officers, existence of general training and the number of hours required, existence of in-service search and seizure training and the number of hours and testing required, existence of policies and procedures on search and seizure, and means of advice available to officers about search and seizure questions. These data comprise Part 1. For purposes of comparison and interpretation of the police officer test scores, question responses were also obtained from other sources. Part 2 contains responses from 36 judges from states with search and seizure laws no more restrictive than the United States Supreme Court decisions, as well as responses from a demographic and work-experience questionnaire inquiring about their age, law school attendance, general judicial experience, and judicial experience and education specific to search and seizure laws. All geographic regions except New England and the Pacific were represented by the judges. Part 3, Comparison Data, contains answers to the 14 test questions only, from 15 elected district attorneys, 6 assistant district attorneys, the district attorney in another city and 11 of his assistant district attorneys, a police attorney with expertise in search and seizure law, 24 police academy trainees with no previous police work experience who were tested before search and seizure law training, a second group of 17 police academy trainees -- some with police work experience but no search and seizure law training, 55 law enforcement officer trainees from a third academy tested immediately after search and seizure training, 7 technical college students with no previous education or training on search and seizure law, and 27 university criminal justice course students, also with no search and seizure law education or training.