It has been “an ongoing conversation” to get some auto makers to include all their North American plants in Harbour Consulting Inc.'s annual Harbour Report on productivity, says President Ron Harbour.

The 2005 North American report recently was released with some Toyota Motor Corp., Honda Motor Co. Ltd. and Nissan Motor Co. Ltd. plants notably absent, as is the sole Mercedes-Benz U.S. International Inc. (MBUSI) plant in Vance, AL.

As a result, Toyota, Nissan, Honda and Mercedes-Benz are not in the report's overall assembly rankings by company.

The Japanese Big Three are unwilling to open the doors to all of their North American plants, and MBUSI officials say they rely on their own internal indices.

Toyota's Princeton, IN, truck plant, which builds the Tundra fullsize pickup truck and Sequoia fullsize SUV, never has participated in the Harbour Report.

Harbour says he has tried to appeal to Toyota's sense of integrity, but it hasn't worked thus far.

“As a company we value the Harbour Report,” says a Toyota spokesman. “It is a very positive way for the industry to benchmark productivity. However, some of our plants and lines currently do not participate in the report. The decision is evaluated on an ongoing basis, and it's indeed possible these plants and lines will participate in the future.”

Because the report is made public in North America, Harbour says he is unable to refuse to provide non-compliant auto manufacturers with their competitors' results.

In contrast, Harbour productivity reports in Europe, Asia and South America are kept private.

Honda's Alliston No.1 plant in Canada, its new Lincoln, AL, plant and its El Salto, Mexico, plant did not participate in this year's report.

Harbour takes issue with Nissan for not including its plants in Aguascalientes and Cuernavaca, Mexico.