Nine black Boston police supervisors are suing the city of Boston in federal court, claiming the test for promotion to lieutenant is discriminatory against minorities.

Promotions to lieutenant in the Boston Police Department are based heavily on a written multiple-choice exam, which minority officers tend to score lower on than white officers.

“[The exam] doesn’t really take into account the skills a supervisor would need to perform the job,” said Larry Ellison, president of the Massachusetts Association of Minority Law Enforcement Officers. “Very little of [what is on the exam] is related to the position.”

BPD declined to comment on pending lawsuits, said a police secretary who asked to remain anonymous.

Ellison said once those who score highest on the exam are promoted, they are sent to the police academy for four weeks of training on the skills necessary for the position.

The department trains the highest scorers rather than promoting those who already have the skills necessary for leadership positions, he said.

Ellison said he has personal experience with the lieutenant exam.

“I’ve taken several exams, and they have very little to do with the job,” he said.

The arrival of exams for detective positions in the past 10 years or so demonstrates the politics and bias in the promotion process, Ellison said.

Previously, he said, there was no exam for the detective position, and it was based on the commissioner’s discretion, which took into account leadership skills and experience.

“I would like to see a police department that is reflective of the population of the city, and Boston is not that,” Ellison said.

There are 23 captains in the Boston police department, one of who is black, Ellison said.

Out of the department’s 51 lieutenants, two are black and one is Asian.

Ellison said the testing methods could be fixed by being more similar to those of the Massachusetts State Police.

“You cannot even take a state police promotional exam with less than 10 years on the job,” Ellison said.

BPD only requires officers to be in grade at that height for one year before they take the next exam, Ellison said.

Massachusetts State Trooper Todd Nolan declined to comment on the basis that the case does not impact the state police, as the BPD and Massachusetts State Police are separate departments.

Boston University School of Law Professor Michael Harper said the case is being brought forth on the theory of “disparate impact,” which occurs when a business practice, such as a test, has a disproportionately negative effect on a minority group.

If a practice does cause a disparate impact, it must be justified by a business necessity or be related to job performance, Harper said.

Harper said if the lieutenant exam is shown to have a disparate impact, “the Boston Police Department must be able to prove that success on the test correlates with job performance.”

“If [the lieutenant exam] has disparate effects and cannot be shown to be job related,” he said, “then it is illegal under Title VII of the 1964 Civil Rights Act.”