DETROIT -

Despite earning their lowest scores in more than a decade, Toyota and Honda held onto the lead spots in the 12th annual North American Automotive OEM-Tier 1 Supplier Working Relations Index Study.

Meanwhile, Chrysler and General Motors saw continued improvement resulting in best-ever scores this year, and Ford fell slightly but remained in third place overall.

The North American Automotive OEM-Tier 1 Supplier Working Relations Index Study, conducted annually by Planning Perspectives Inc. of Birmingham, Mich., tracks supplier perceptions of working relations with their automaker customers in which they rank the OEMs across the six major purchasing areas broken down into 14 commodity areas.

The results of the study are used to calculate the Working Relations Index, consisting of five key behavioral Component areas — OEM Help, OEM Hindrance, Relationship, Communication and Profit Opportunity — broken down into 17 variables that contribute to good supplier relations.

This year, 564 supplier personnel from 439 Tier 1 suppliers participated, representing 62 percent of the six automakers’ annual buy.

While still holding onto first and second place overall respectively in this year’s rankings, Toyota and Honda — which had the highest scores in the study in the 2005-07 period — fell this year to their lowest scores in 11 years while Chrysler, GM and Ford improved dramatically and as a group, achieved their highest scores.

Nissan’s rankings also fell during the same period but showed slight improvement this year; however, Planning Perspectives noted that Nissan could lose fourth place to GM or Chrysler next year if these companies continue their current trend lines. Only eight points separate the three.

For 2012, Ford fell slightly but continues to lead the U.S. automakers and remains in third place overall even though its improvement has been stalled for the last three years. Nissan showed slight improvement and is in fourth place, while GM and Chrysler continue to improve and remain in fifth and sixth place respectively.

Although some automakers showed gains in the data, the overall picture is not rosy, said John Henke, president of Planning Perspectives and a professor at Oakland University.

“It’s a concern that all of the automakers are ‘converging toward mediocrity’ in the overall low Adequate range in the Working Relations Index, which is equivalent of a grade C in academia,” Henke said.

Forty percent of suppliers still rank the Detroit 3 and Nissan in the Poor–Very Poor range, which Henke attributes to scoring improvements resulting from quick fixes by U.S. automakers on easily identifiable problems, such as Chrysler improving processes to quickly rectify late payment issues.

Also, Henke said, there is still considerable performance variation among all OEMs’ purchasing areas except GM’s; implementation of the Working Relations variables year-to-year is inconsistent within each OEM; and there’s inconsistency in support of positive working relations between automakers’ top purchasing executives and their individual buyers.

Good working relations with suppliers are critical to automakers, PPI noted.

Over the years, the study has shown that automakers with Good-Very Good working relations benefit as their suppliers are more willing to invest in and share new technology; support the automaker beyond contractual terms; assign their A teams in terms of OEM support personnel; communicate more openly with the OEM; and give greater price concessions to OEMs.

Conversely, the PPI study has shown that automakers with poor relations with their suppliers receive smaller price concessions and must work harder to get them; are supported by less experienced supplier personnel; and typically are not among the first to get their suppliers’ best ideas and innovations.

Henke said the most important factor in improving supplier relations is consistency in managing the purchasing-engineering-quality interfacing activities.

“The automakers must understand that maintaining supplier working relations is a never-ending process; it’s dynamic, not static, and requires continuous attention,” he said. “Decades ago, U.S. automakers thought they were building the best vehicles possible, until the Japanese came here and suddenly everything changed.

“Automakers now expect 100 percent quality and are building the best vehicles they ever have. It is going to take that kind of focus and discipline to consistently achieve high levels of supplier relations, and the payoff will be just as valuable.”

To improve buyer performance, Henke recommends that automakers focus resources and training on improving working relations quality with measurable performance metrics, just as they did to improve product and manufacturing quality, and better train buyers to ensure they understand that poor supplier relations cost the automaker money and will not be tolerated.

For the past three years, the North American Automotive OEM-Tier 1 Supplier Working Relations Index Study has also included Volkswagen, BMW and Mercedes-Benz. While these results are not yet included in the official Working Relations Index due to lack of historical data, PPI reports certain broad trends as credible.

For instance, since 2010 all three German automakers have fallen in their WRI rankings as dramatically as have the Japanese domestics, and for the same reasons: Wide variations in managing the Working Relations Components across purchasing areas.

In addition, trust has fallen all three years for the German automakers, while it has increased significantly during the period for both the U.S. and Japanese automakers.

Overall rankings combining the Big Three German, Japanese and U.S. automakers put BMW and Mercedes at the top of the nine automakers, with VW at the bottom.