DULUTH — There are racial disparities in the Duluth Police Department's arrests and use of force, but the numbers used to prove it caused a public rift this week between local law enforcement watchdogs and data collectors hired by the Police Department.

Duluth's Law Enforcement Accountability Network (LEAN) this week responded to a recent report by Seattle-based Police Strategies LLC with an analysis that questioned the company's methodology and ethics and raised concerns about the background of co-founder Bob Scales, who presented the data at a public forum in late March. The department hired Police Strategies in response to a call from the Duluth branch of the NAACP, which told law enforcement officials to end oppression in law enforcement.

"There's a real danger with data because it has both the power to inform, but also mislead," Jamey Sharp of LEAN said.

An attorney for Scales and Police Strategies sent LEAN an e-mail accusing the group of volunteers of making false and defamatory statements, and threatened to file a lawsuit against the organization.

"To be clear, we do not question your right to challenge the methodology, findings or ultimately 'credibility' of the Police Strategies report," wrote the attorney, Carl J. Marquardt. "These are matters upon which reasonable people may agree, and Mr. Scales welcomes further discussion and reasoned dialog on these points. But to assert that someone is 'unethical,' simply because you disagree with them, is unfair — and in this case, false."

LEAN later tweaked some wording of its analysis, at least twice removing the word "ethics" from the report.

At a quickly arranged media conference held on Zoom on Wednesday afternoon, Scales highlighted his credentials — including a law degree from the University of Washington School of Law, formal training in statistics, and work with 90 law enforcement agencies in eight states.

It's been just more than a year since LEAN issued a report finding that half of the citizens involved in use-of-force incidents that year were people of color, even though non-white residents comprise just 10% of the city's population. At the time, the Duluth branch of the NAACP told the Police Department that it expected to see numbers proportionate to the racial demographics in this region by December 2022.

Police Strategies, presenting at a public forum in Duluth in late March, offered a 172-page report alongside a PowerPoint presentation with much of it explaining its methodology. When reporting racial disparities in use of force, for instance, it starts with arrests: Black and Native American people who are under arrest are twice as likely to be involved in a use-of-force incident than white citizens.

At least one-third of Scales' nearly two-hour presentation in March was about using activity-based benchmarks rather than population. Population is the traditional method, he said, but less accurate.

"In order for population benchmarks to be valid, we have to make a lot of assumptions," Scales explained. "We have to assume everyone in the population commits crimes at the same rate."

Police Strategies' report found that Black and Native American people are nine times more likely to be identified as subjects in reported crimes than would be expected based on their percentage of the local population. White and Asian people are both less likely to be reported by 40% and 70% respectively.

The report shows disparities, Scales said, but does not show why they exist.

Sharp said that one reason LEAN released its analysis was to create a public record of its discontent with Police Strategies' methods and the company's founders, who both have background in policing. Scales has worked alongside the Seattle Police Department as a compliance officer, according to his LinkedIn profile, and his partner Mike Sanford was assistant chief of the same department.

LEAN's timing with its analysis was purposeful. The city is in the process of finding a group to conduct a racial bias audit.

"It's important for us to show what could happen if the community isn't properly involved in the process," Sharp said.