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Trial Court Perforrmance Standards & Measurement System

Measure 3.2.2: Random Jury Selection Procedures

This measure determines whether a court is using random selection to select prospective jurors from the juror source list(s). Data are obtained by comparing actual prospective juror panels with those that would be expected if random selection was used.

Planning/Preparation. Although courts may say that all names are considered for selection, some statutes, rules, or jury plans specify that strata be observed. In such cases, courts draw names to represent each strata equally or to represent each strata according to some ratio. For instance, some jurisdictions draw by district strata so that the number of names selected from each district is in proportion to the population of the district as compared with the population of the whole jurisdiction. If the source list equally represented each district, a random selection would equally represent each district, to within a small margin of error. These stratified selections are intended to overcome any unequal representation in the source list or lists. However, before applying such techniques, courts should ensure that they are allowed by some authority.

Measures of randomness can be very complex.11 For this measurement, it is recommended that courts compare several observations with expected values. Although deviations from expectations are in some cases proof of randomness, persistent patterns of nonexpected results should require investigation. For instance:

  • A panel of 30 prospective jurors, all male, is expected to occur in every billion panels. One occurrence is reason for great amazement; two occurrences should provoke great concern.

  • Although the alphabet has never been shown to produce a bias, a group of prospective jurors in alphabetical order, or representing only a portion of the alphabet, raises questions of inclusiveness or discretion.

  • A potential jury pool consisting of more than one individual with the same last name or the same address can be expected to occur occasionally but should be checked if occurring regularly.

  • The same people often are called for jury service year after year or several times within the same year. Repeat selections are expected. If 10 percent of the list is selected each year, 1 percent will be selected in 2 successive years and .1 percent will be selected 3 successive years. Values greater than this need to be investigated.

Data Collection. This measure is conducted by examining the list of persons reporting for jury service. These persons may be the entire pool of prospective jurors or, if persons are brought to the court in panels, a number of panels could be examined. Several hundred names should be adequate for these examinations.

If suspicious patterns are found, persons reporting in at other court or jury terms should be examined. If the patterns persist, problems clearly exist. If the patterns are related to the date of service, problems likewise may exist. Patterns to examine are:

  • Alphabetical distribution. Half of the last names should be grouped A through K. Deviations of more than a few percent should be investigated to examine the alphabetical distribution of the source list or lists.

  • Alphabetical inclusiveness. The last names of those serving should represent the entire alphabet. Omissions of the top or bottom of the alphabet should be examined because such omissions would indicate that the whole list was not used. Panels of persons whose last names contain only a portion of the alphabet are probably being called in via a recording that identified individuals to report by last name. This practice should be replaced with one that uses random numbers to select individuals.

  • Geographical distribution. To the extent possible, the panels or pool of prospective jurors should represent the entire jurisdiction. Lack of representation for a distinct area of the jurisdiction could indicate that a geographical listing such as the voter list is being used sequentially rather than by a random selection from the entire list.

Data Analysis and Report Preparation. Nonrandom results are usually the result of the use rather than the generation of random numbers. The problem is in how these numbers are used to select names. If nonrandom results are discovered, detailed discussions with those making selections (i.e., data processing or court staff) are needed. Factors to examine include:

  • Are the same key factors used for each selection?12 If a random start/fixed interval method is used, the start number must be randomly selected in the range from one to the interval number. (If 100 names are desired from a list of 1,000 names, the interval is 10. If "2" is randomly selected, the names at 2, 12, 22, 32, etc., in the order are selected.)

  • If a computer random number generator is used, are the input numbers or seeds changed each time the program is run?

  • Are names held out or passed over due to permanent exemptions or prior service? If these names represent more than a few percent of the source list, this could be the cause of the problem.

  • Are the lists or files thought to be random actually sequential lists or files by alphabet or geography? Voter registration lists are often geographically separated by precinct, ward, or district. Lists ordered by voter registration number may have an age order with older citizens having lower voter numbers.

  • Do the selected names represent the same list? If a printout of the voters list or merged lists contains the same number of pages of "A’s" and "W’s," the selected names should have equal numbers of "A’s" and "W’s." The same list could be counted by ZIP Code, and the distribution of those selected should match the distribution of the source list. That is, if 10 percent of the names on the source list has ZIP Code 22180, about 10 percent of those selected should have that ZIP Code.

The lack of proper numbers for certain demographic groups (e.g., young or black) probably is due to the shortcomings of the source list rather than a problem of randomness. This lack of representation is the topic of the next measure.

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11 D.J. Knuth, The Art of Computer Programming, Semi-Numerical Algorithms, vol. 2, 2d ed. (Reading, MA: Addison-Wesley, 1981).
12 National Center for State Courts, A Supplement to the Methodology Manual for Jury Systems: Relationships to the Standards Relating to Juror Use and Management (Williamsburg, VA, 1987), pp. 10-15.

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Go to Standard 3.2

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Copyright © 2001 National Center for State Courts
Last Modified: January 23, 2005