SHIRLEY — The Board of Selectmen — acceding to the Board of Assessors’ recommendation — voted unanimously to retain the town’s single tax rate for another year.

In accordance with state law, the assessors posed the question at a public hearing, which was held during the Nov. 3 selectmen’s meeting.

Principal Assessor Rebecca Caldbeck, board Chairman Joseph Saball and assessor Ronald Marchetti presented classification facts and figures to make the case for a single tax rate versus a split rate that would shift tax burden to commercial property owners.

With just 10 percent of the town’s total assessed property in the commercial category and the rest residential, that set-up wouldn’t make sense in Shirley, the assessors said. The turning point at which it would work is when commercial/industrial property reaches at least 20 percent of all properties in Shirley, Caldbeck said.

Based on the town’s total assessment, the estimated tax rate for next year is $11.18 per $1,000 of value, Caldbeck said. That value is lower this year, with an average single-family home valued at $301,562.

When property values go down, the tax rate goes up, she explained. Translated to a tax bill, the owner of the average home pays $3,371, an increase slightly less than the two and a half percent allowed by state law.

Saball explained that splitting the tax rate, placing a higher burden on businesses, would overburden them.

The assessor unanimously voted to retain the single rate, but that decision is up to the selectmen, Saball said.

For his part, Marchetti described work in progress to compile a list of commercially-zoned parcels in town, complete with maps, charts and graphs and notes on future opportunities for the properties.

The effort was in response to a push by Selectman Armand “Andy” Deveau four months ago to explore economic development options in Shirley, Marchetti said.

John Oelfke did the work under the auspices of the tax work-off program, he said.

Compared to Ayer and Devens, which have split tax rates, Shirley offers a “desirable environment” for business, Marchetti said. Noting those here now, he said that Bemis, for example, does much for the community besides pay taxes, supporting the schools and sponsoring programs.

“I believe most businesses in town have that sense” of commitment to the community, he said.

The selectmen voted unanimously for a single tax classification.

But the assessors do not actually set the tax rate. The Department of Revenue does that, town administrator Kyle Keady said.

The full presentation is posted on the assessors’ page of the town Web site,