TREND WATCH : <i> A roundup of business developments spotted by other publications.</i>

Labor Incentive: Federated Department Stores Inc. is switching its sales staffs to commission and other forms of incentive pay. A recent national survey of retailers by Ernst & Young found the use of incentives rising. Last year, 92% of the department stores, discounters and specialty chains that responded to the accounting firm’s survey said they use cash and non-cash incentives to motivate their sales staffs. Ernst & Young surveyed 86 retail companies to assess the benefits of incentive pay for salespeople. Sixty-eight percent said incentives improved sales, but only 34% said it improved customer service and 25% said it reduced employee turnover. Atlanta Constitution

Digital Audio Segment: A joint venture between NV Philips and Tandy Corp. aims to capture a hybrid segment in the consumer electronics market. With digital audiotape coming on line, Philips and Tandy will introduce a tape deck that will reproduce the digitized sound on standard tape cassettes. The product will be called a digital compact cassette player. The projected price at Tandy’s Radio Shack is $600, compared to $800 for the least-expensive machine that plays the specialized digital audiotape. Detroit Free Press

Heck’s Angels: Sales continue to grow at Harley-Davidson Inc., the Minnesota-based company that made headlines in the 1980s by recapturing the big motorcycle market from the Japanese, but the road ahead seems not so smooth. Problem: Too few Americans are riding big bikes. The company reports that the market for motorcycles with engines of 850 or more cubic centimeters declined to 75,000 last year from 124,000 in 1983. During the same period, its market share increased to 60% from 20%. “The challenge that all motorcycle manufacturers face is to get people back on motorcycles,” said Roger Lambert, a spokesman for Honda of America Manufacturing. Harley’s strategy includes promoting motorcycle clubs that will appeal to women. Milwaukee Journal