If Toyota Motor Corp. needs affirmation that its strategy to collaborate with suppliers is working, it should review the findings of the 28th Annual Supplier Survey, conducted this spring for Ward’s.

Japan’s No.1 auto maker ranks first among 79 Tier 1 supplier representatives who were asked to identify their three most-preferred auto maker customers.

With 51.9%, Toyota tops DaimlerChrysler Corp. (46.8%), which is widely recognized for improving the supplier/OEM relationship in the 1990s.

Chrysler’s crosstown rivals fared well in the survey, as well. Ford Motor Co. and General Motors Corp. (at 44.3% and 38.0%, respectively) beat out Honda Motor Co. Ltd. and Nissan Motor Co. Ltd. for the No.3 and 4 slots in the survey.

The study was conducted between May 2 and June 16 by Prism Business Media’s Marketing Research Dept., a corporate sibling of Ward’s based in Minneapolis, MN.

The sample was constructed carefully to ensure a broad cross-section of suppliers. For instance, to prevent the large organizations of Delphi Corp. and Visteon Corp. from skewing results, participation of employees from each of the two companies was limited to 1.5% of the sample.

Overall, 157 supplier representatives answered the question from all tiers of the supply chain. However, Ward’s factored out the 78 non-Tier 1 responses, because Tier 1 suppliers deal most directly with OEMs and are in the best position to answer the question.

With all 157 responses tallied, the top four players were the same, in slightly different order. Ranking No.1 was DaimlerChrysler, followed in order by Toyota, General Motors and Ford.

The survey findings conflict slightly with the Working Relations Study released recently by Planning Perspectives Inc. in Birmingham, MI.

The Planning Perspectives study asks the question: “Based on your firm’s working relations with the OEM and assuming equivalent sales and profits from each OEM, to what degree is the OEM a preferred customer?”

The question is asked with regard to North America’s top vehicle producers: GM, Ford, Chrysler, Toyota, Honda and Nissan. For the past five years, the scores have changed but the rankings have been the same in the Planning Perspectives study: Toyota has been No.1, followed in order by Honda, Nissan, Chrysler, Ford and GM.

Planning Perspectives President John Henke Jr. says the divergent results reflect the nature of the individual queries.

The Ward’s question draws a connection to a supplier’s revenues and profitability, so suppliers with significant Big Three business are more likely to score GM, Ford and Chrysler higher than in the Planning Perspectives study, which looks more specifically at the health of the working relationship, Henke says.

“We both have very legitimate and accurate results,” he says. “These results are reasonably consistent.”

Meanwhile, a few respondents to the Ward’s question wrote in other answers in identifying with whom they prefer to do business: Mazda Motor Corp., BMW AG, Hyundai Motor Co. Ltd., Kia Motors Corp. and Fuji Heavy Industries Ltd. (Subaru).