Liacos, J.
The Commonwealth has appealed from an order issued by a Superior Court judge dismissing indictments returned against fifteen Hispanic defendants by Essex County grand juries. Mass. R. Crim. P. 15 (b) (1), 378 Mass. 882 (1979). The judge granted the Commonwealth’s motion to stay his order pending decision by an appellate court. We granted the Commonwealth’s petition for direct appellate review.
Essex County grand juries returned indictments against the fifteen Hispanic defendants in February, March, and August, 1981. The attorneys representing these defendants filed a motion in the Superior Court in Essex County to dismiss the indictments on July 3, 1981.
Mass. R. Crim. P. 13 (c), 378 Mass. 871 (1979). The defendants contended that the procedures used in selecting and empanelling grand juries for Essex County for the years 1976-1981 were not neutral and resulted in substantial underrepresentation of Hispanic persons. They claimed that these procedures violated the rights guaranteed them by the Fourteenth Amendment to the Constitution of the United States, by art. 12 of the Massachusetts Declaration of Rights, and by G. L. c. 234.
The judge conducted evidentiary hearings spanning eleven days from December, 1981, through June, 1982. Based on the testimony of the defendants and the definition provided by the 1980 census of population and housing,
the judge, in an interim
order dated June 11, 1982, found that all the defendants were Hispanic. The Commonwealth does not contest this finding.
The Commonwealth contends, however, that the judge erroneously decided that the indictments returned against the defendants violated their rights under the equal protection clause of the Fourteenth Amendment to the United States Constitution and art. 12 of the Declaration of Rights of the Massachusetts Constitution. We conclude that we need not decide whether the evidence in this case supports the judge’s findings of purposeful discrimination in violation of the equal-protection clause under the “rule of exclusion” espoused by the United States Supreme Court.
See
Castaneda
v.
Partida,
430 U.S. 482, 494 & n.13 (1977). We agree with the judge that the defendants demonstrated a prima facie case of systematic, albeit unintentional, discrimination against Hispanic persons in violation of art. 12 of the Declaration of Rights.
The order of the judge dismissing the indictments against the defendants is therefore affirmed.
1.
The factual background. A. Evidence of underrepresen-tation.
The parties stipulated, based on the 1980 Federal census, to the number of persons of Hispanic origin in the total Essex County population, as well as to the percentage of these individuals in the county as a whole and in the various cities and towns. Of 465,477 adult persons in Essex County, 9,225, or 1.98%, were of Spanish origin; 94.92% of the Spanish origin population was concentrated in ten cities and towns, with Lawrence and Lynn containing the largest percentages.
The parties also agreed that between 1976 and 1981, 328 individuals were summoned for grand jury duty in Essex County. The record does not indicate how many of these persons actually served on a grand jury. The defendants mailed to these 328 individuals a questionnaire in which each person was asked to designate his or her ethnic identification. Based on the returned questionnaires and on personal investigation, the parties agreed that 321 of the 328 individuals summoned for the grand jury between 1976 and 1981 were non-Hispanic persons. Although the other seven persons could not be found, both parties agreed that the odds were very small indeed that they were of Spanish origin, based on their surnames and on interviews with their neighbors and other persons who knew them. The court-appointed expert testified that the probability of three of the seven remaining persons being of Hispanic origin was approximately three in 10,000.
During the evidentiary hearings, the defendants and the Commonwealth presented witnesses who were experts in statistical analysis. Dr. Thomas J. Marx, the defendants’ expert, testified that a random selection of prospective grand jurors from Essex County would have produced, at minimum, three Hispanic persons.
The expert concluded that the absence of Hispanic persons from the list of grand jurors in the years at issue constituted strong evidence of a nonrandom selection procedure and the existence of bias against members of the Hispanic population.
Dr. Jeffrey W. Eiseman, the Commonwealth’s expert witness, utilized a different test for analyzing the data on Hispanic persons in Essex County.
Dr. Eiseman calculated underrepre-sentation on a community-by-community basis as opposed to a county-wide basis, since the established practice seems to have been that each town or city in Essex County sends, in response to writs of venire facias, an equal number of veniremen to a panel.
In determining the minimum number of Hispanic persons expected to be drawn, based on their proportional representation in Essex County, the expert adjusted his figures by estimating the percentage of Hispanic persons who would not be eligible to serve on a grand jury. Dr. Eiseman thus concluded that if the statistical analysis was conducted on a community-by-community basis and took into account only those Hispanic persons who presumably were citizens or could speak English sufficiently, the defendants could not demonstrate that the observed underrepresentation resulted from nonrandom selection. On cross-examination, however, Dr. Eiseman did admit that if the analysis was performed on a county-wide basis there would be an inference that a nonrandom, discriminatory selection procedure was utilized.
The court-appointed expert, Dr. Michael Malee, was qualified in statistical analysis in the social sciences. Although
Dr. Malee recognized that the tests utilized by both parties’ experts were common in social science research, he concluded that neither he nor any statistician could tell the court precisely which standard to apply, or whether any standard could determine bias in a jury selection procedure. He testified, however, that Dr. Marx’s formula was appropriate, and that the probability of obtaining zero Hispanic persons from a
random
sample of 321 persons, given a percentage of 1.98% Hispanic persons in the county population, was slightly over one in 1,000, or sixteen in 10,000 (.0016) exactly.
B.
The Essex County grand jury selection system.
The defendants were prepared to present detailed evidence in support of their contentions that the grand jury selection system in Essex County was susceptible of abuse, or was nonneutral. The defendants, however, chose not to present such evidence when the judge ruled that their burden on this element was satisfied by the Commonwealth’s concession that the key man system of jury selection was in operation in Saugus and Lynnfield. See note 17,
infra.
The Commonwealth presented testimony by public officials of ten communities in Essex County who described the procedures utilized by them in their communities to compile the master lists of prospective grand jurors during the relevant period. The ten communities from which these witnesses were drawn represent the communities in which approximately 94.9% of the county’s Hispanic population resided. In the communities of Lawrence, Gloucester, and Peabody, the official responsible for drawing up jury lists would choose names at random out of a street listing book and send a questionnaire to each person so selected. These officials testified that they could use their discretion in picking individuals from the street list, and the Lawrence and Peabody officials stated that it was permissible to pick persons known to them from the street listing. These three communities, combined with Saugus and Lynnfield, contained 66.6% of the county’s Hispanic population.
Town or city officials testified that in the communities of Salem, Methuen, Beverly, and North Andover they would
choose names at specific intervals, e.g., every fifth or tenth name, from a list of residents, or one name after another, in equal numbers from each sector of the city. In compiling the lists, these officials would observe the surnames of the residents from the street listings or census records. These four communities accounted for approximately 11% of the county’s Hispanic population. The other three communities of Lynn, Haverhill, and An-dover utilized a computer which randomly drew names of adults from street lists. The officials of these communities sent out jury questionnaires to individuals on these computerized lists.
Eighteen and two-tenths percent of the Hispanic population of Essex County resided in these communities.
Most of the witnesses testified that persons chosen from the street or census lists as prospective jurors from 1976 through 1981 were not screened to determine their eligibility to become jurors but merely were sent the standardized jury questionnaire.
The questionnaire was used to determine whether prospective jurors had a characteristic which could render them ineligible for service, e.g., alien status, physical or mental incapacity, holding certain public employment, or having a particular criminal record. See G. L. c. 234, §§ 1, 1A, & 4. Only when the questionnaires were returned would persons who were found ineligible to serve on a jury be eliminated from the list.
As grand jurors were needed for an Essex County panel, the city councillors or selectmen from each community would conduct a blind draw from the master list of a sealed envelope or capsule containing a juror’s name.
C.
The order by the Superior Court judge.
The judge decided that the defendants’ underrepresentation claim should be evaluated by reference to the percentage of Hispanic and white adults in the entire Essex County population, as opposed to estimating these percentages on a community-by-community basis. In support of his decision, the judge cited the enabling statute which provides for the recruitment of grand jurors from the county as a whole. G. L. c. 277, § 2G. Furthermore, the judge reasoned that, even if the grand jury selection system discriminated against residents in larger urban centers because it took roughly the same number of jurors from each community, this fact did not rebut the inference of county-wide systematic underrepresentation, especially if the system reduced the chances that Hispanic persons would be selected.
The judge found unpersuasive the Commonwealth’s claim that a county-wide analysis distorted the statistics because it did not consider the percentage of ineligible Hispanic persons in the population. The judge reasoned that the Commonwealth failed to rebut the inference of discrimination which was established by the defendants’ showing of systematic underrepresen-tation of Hispanic persons. The Commonwealth failed to present credible, cogent evidence of the percentage of Essex County Hispanic persons who were ineligible for grand jury service. See
Castaneda
v.
Partida,
430 U.S. 482, 498-499 (1977).
The judge proceeded to determine whether the defendants had made out a prima facie case of discrimination under the equal protection clause of the Federal Constitution and art. 12 of the Massachusetts Declaration of Rights. The judge found that the Hispanic defendants belonged to a “recognizable, distinct class, singled out for different treatment under the laws, as written or as applied.”
Id.
at 494. The judge concluded that the defendants, as required by the Federal Constitution, showed both total exclusion and disproportionate underrepre-
sentation of Hispanic persons over a significant period of time. The judge also decided that under art. 12 the defendants demonstrated a “substantial, identified exclusion of [a] distinct, qualified segment of society.”
Commonwealth
v.
Bastarache,
382 Mass. 86, 102 (1980).
Based on the parties’ stipulation that 321 of the 328 members of the Essex County grand jury venires between 1976 and 1981 were non-Hispanic persons, and based on evidence that the chances of finding three Hispanic persons among the missing seven members were three in 10,000 (.0003), and that the probability of drawing no Hispanic persons from a random sample of 321 adults in Essex County was sixteen in 10,000 (.0016), the judge decided that underrepresentation of Hispanic persons was statistically significant.
On the basis of this evidence, the judge concluded that
both
disproportionate underrepresentation and total exclusion of Hispanic persons from the Essex County grand jury venires had taken place from 1976 to 1981.
The defendants satisfied the second and final prerequisite of a prima facie case under a Federal equal protection claim, the judge held, because stipulations and evidence presented by the Commonwealth conclusively showed that the Essex County grand jury selection procedure was “susceptible of abuse or . . . not racially neutral.” See
Castaneda
v.
Partida, supra
at 494.
The judge then investigated whether the Commonwealth had met its burden of rebutting, under the Federal Constitution, the inference of intentional discrimination demonstrated by the
defendants’ prima facie case. The judge invited the Commonwealth to offer evidence which would show that the absence of Hispanic persons from the grand jury venires resulted from a neutral nondiscriminatory factor or from factors such as statutory ineligibility, the greater mobility of the county’s Hispanic population, or their failure to receive or to reply to a summons. After reviewing the Commonwealth’s evidence, which consisted entirely of the previously described testimony concerning the operational procedures of the jury selection system in ten Essex County communities, the judge determined not only that the Commonwealth failed to rebut the prima facie case but also that the system was conclusively shown, by the Commonwealth’s evidence, to be susceptible of abuse and not ethnically neutral. Specifically, he found that 66.6% of the county’s Hispanic persons resided in communities using the key man system to compile the initial list of prospective grand jurors, and 73.8% of the Hispanic persons lived in communities where the initial selection was either a key man or manual system.
The judge noted that a computerized system of compiling lists of prospective jurors was in effect in communities which contained only 22% of the county’s Hispanic population.
The judge also decided that the Commonwealth’s evidence failed to rebut the prima facie case of discrimination under art. 12. The judge interpreted
Commonwealth
v.
Bastarache, supra,
as proscribing, under art. 12, any jury selection system which results in intentional or unintentional discrimination by a significant underrepresentation or total exclusion of one of the protected groups referred to in art. 1. See
id.
at 101; art. 1 of the Massachusetts Declaration of Rights, as amended by art. 106 (equality under the law shall not be abridged based on sex, race, color, creed, or national origin). The judge there
fore ordered the dismissal of the indictments against the defendants.
2. 77ze
claims of error.
A.
Sufficiency of evidence.
In reviewing a judge’s decision, before trial, to dismiss the indictments against the defendants, this court must determine whether the evidence supported the judge’s factual findings and whether the findings warranted the rulings of law. See
Commonwealth
v.
Botelho,
369 Mass. 860, 868 (1976).
We find unpersuasive the Commonwealth’s claim that the defendants did not show disproportionate underrepresentation in the Essex County grand jury venires during the years 1976 through 1981. Our General Laws require the drawing of juries on a county-wide basis. The judge correctly determined the percentage of Hispanic persons by reference to the entire county and not on an individual community basis. See G. L. c. 277, § 2G. Even assuming that the Essex County selection system discriminates against all residents of the larger urban areas by drawing approximately the same number from each community regardless of size, this would not refute the existence of systematic county-wide discrimination.
The judge also correctly refused to comply with the Commonwealth’s request that, in determining underrepresentation, he consider only the percentage of Essex County Hispanic persons who were eligible to serve on a grand jury. In the challenged selection procedure, it appears that local officials compiled lists of
prospective
grand jurors only, and did not investigate whether a resident was a United States citizen or was able to speak and understand English, both of which could ultimately lead to exemption from jury service. See G. L. c. 234, §§ 1 & 4. As the local officials testified, statutory ineligibility could be determined only by the answers to the standardized juror questionnaires which the residents selected were required to complete and return.
Furthermore, the burden was on the State to present evidence of ineligibility once the defendants established underrepresentation based on the per
centage of their minority group in the general population as compared with their representation in the grand jury venire. See
Castaneda
v.
Partida,
430 U.S. at 498-499. There was no such competent evidence offered.
Based on the parties’ stipulations and the evidence, the judge properly could find that Hispanic persons were both totally excluded from, and substantially underrepresented in, the Essex County grand jury venires during the years in question.
The Commonwealth claims that the defendants did not show that the Essex County grand jury selection procedure made significant use of a key man system merely because the Commonwealth conceded that a key man system existed in the towns of Lynnfield and Saugus.
Hispanic persons residing in these two communities comprised only .9% of the Hispanic population in Essex County. The judge found that a key man system was also utilized in Lawrence, Peabody, and Gloucester.
Evidence of selection procedures in Lawrence, Peabody, and Gloucester, together with Saugus and Lynnfield, clearly established the existence of a key man system in communities wherein resided approximately 66.6% of the county’s Hispanic population.
We conclude that the record in this case amply supports the findings of the judge. We turn now to examine whether the judge properly ruled that the indictments be dismissed under State constitutional law.
B.
The claim under art. 12.
The Commonwealth claims that the judge incorrectly decided that any unintentional discrimination against Hispanic persons resulting from the key man system, or any other nonrandom jury selection system, violates art. 12 of the Massachusetts Declaration of Rights.
We have interpreted sections of our Declaration of Rights so as to provide broader protection to criminal defendants than is available under corresponding provisions in the United States Constitution. See
Attorney Gen.
v.
Colleton,
387 Mass. 790, 796, 801 (1982);
Commonwealth
v.
Soares,
377 Mass. 461, 475-477, cert. denied, 444 U.S. 881 (1979). Two recent decisions of this court indicate through their analysis of State constitutional and statutory provisions that art. 12 safeguards defendants against systematic, albeit unintentional, discrimination against their protected class resulting from a nonrandom jury selection system.
See
Commonwealth
v.
Bastarache,
382 Mass. 86, 101-103 (1980);
Commonwealth
v.
Soares, supra
at 478-479, 481-482.
In
Soares
we held that the use
of peremptory challenges by a prosecutor to exclude black persons from a petit jury denied the defendants their rights under art. 12 to be tried by a jury “fairly drawn from the community.”
Id.
at 463. Although
Soares
involved peremptory challenges in the empanelment of a petit jury, we analyzed and set forth in that decision the essential safeguards of art. 12 with respect to jury selection in general.
Id.
at 478-479, 481-482. We reasoned that under art. 12 a “defendant is constitutionally entitled to a jury selection process free of discrimination against his grouping in the community, ’ ’ and that a fair jury is one that represents a cross section of individuals and ideas in the community.
Id.
at 478, quoting
Commonwealth
v.
Rodriquez,
364 Mass. 87, 92 (1973). See
Commonwealth
v.
Ricard,
355 Mass. 509, 512 (1969). The groups which art. 12 protects and which cannot form the basis for juror exclusion are the same classes referred to in art. 1 of the Massachusetts Declaration of Rights.
Soares, supra
at 486 n.29, 488-489. We noted in
Soares
that any jury selection system in the Commonwealth, including the compilation of master lists from which venires are drawn, must be carried out on a random basis and must represent a fair cross section of the relevant community.
Soares, supra
at 478 n.13, citing G. L. c. 234A, § 1; 482 & n.21, citing G. L. c. 234, §§ 1-4. We recognized, however, that absolute proportionality would be an impossible objective given the statutorily prescribed methods of jury selection and provisions allowing for the removal of any juror who expressed an interest, bias, or prejudice relating to a particular case.
Soares, supra
at 481-482.
Following the interpretation of art. 12 presented in
Soares,
we stated in
Commonwealth
v.
Bastarache, supra,
that we express “particular sensitivity in analyzing jury selection practices to discrimination against those groupings in the community that are set out in art. 1 of the Declaration of Rights.”
Id.
at 101. In
Bastarache,
we decided that a classification
comprised of younger persons (between the ages of eighteen and thirty-four) did not constitute a protected group for purposes of challenging grand jury selection procedures under the Federal Constitution. Because the defendant did not present in a timely manner his State constitutional challenge to the selection procedure, the court did not directly resolve the State issue. Although we intimated that the defendant’s discrimination claim based on underrepresentation of younger persons would not prevail since this group was not a protected class under art. 1, we stated that substantial, albeit unintentional, discrimination through a jury selection procedure against any group protected under art. 1 would raise a State constitutional question.
Id.
at 101, 102.
The
Bastarache
court also determined that the key man system of choosing juries presented a possibility of abuse by allowing for the selection of jurors “based on subjective considerations.” See
id.
at 102-103. See generally G. L. c. 234, § 4 (resident’s name shall be placed on jury list only upon finding by public official, upon personal knowledge, interrogation, or questionnaire, that resident is of good moral character, of sound judgment, and free from all legal exceptions). To effectuate the compilation of jury lists by random selection, in conformance with art. 12, we suggested, under our superintendence power, G. L. c. 211, § 3, that the Attorney General prescribe random selection procedures for all counties or, alternatively, that the Legislature extend the random procedure provided for in G. L. c. 234A (then applicable to Middlesex County only).
Id.
at 103. In apparent response to the
Bastarache
case, the Legislature amended c. 234A by making the purely random selection procedure applicable to any county designated by this court as a “participating county,” which would result in the abandonment of the key man system, or any other nonrandom system then in effect in those counties. See G. L. c. 234A, § 1, as appearing in St. 1982, c. 298, § 1.
In accordance with the
Soares
and
Bastarache
cases, the Superior Court judge was justified in concluding that the defendants made out a prima facie case of discrimination under art. 12. The Hispanic defendants possessed the rights, under
arts. 12 and 1, to have prospective grand jurors selected by a process which did not systematically discriminate against their protected class, and to have a grand jury venire which represented a fair cross section of the community. Moreover, the defendants were entitled, under the same constitutional provisions, to a jury selection procedure which precluded the possibility of even an unintentional exclusion of prospective jurors based on national origin. The judge properly found that the defendants were all Hispanic persons, that Hispanic persons comprised 1.98% of the Essex County population, and that there was a total exclusion of Hispanic persons from lists of prospective grand jurors in Essex County over the period at issue. The judge also found that during this period a key man system or other nonrandom system of selection existed in Essex County cities and towns where 73.8% of the county’s Hispanic residents lived. Taken as a whole, these findings warrant the judge’s conclusion that the Essex County juror selection system resulted in systematic, albeit unintentional, discrimination against Hispanic persons in violation of art. 12.
The judge invited the Commonwealth to rebut the defendants’ prima facie case. There was no credible evidence presented to rebut the prima facie case. Instead, the Commonwealth’s evidence clearly demonstrated that either a key man system or a nonrandom selection procedure was utilized in communities accounting for more than three-quarters of the county’s Hispanic population. The evidence thus justified the judge’s conclusion that the Commonwealth had not rebutted the prima facie case of discrimination under art. 12.
Since the judge correctly concluded that the previous
Essex County jury selection system violated the defendants’ rights
under art. 12, we affirm his order dismissing the indictments returned against the defendants.
So ordered.