This study investigates the impact of nine new product development (NPD) acceleration approaches on development speed. Our findings from 233 manufacturing firms show that 5 approaches (supplier involvement, lead user involvement, speeding up activities and tasks, training and rewarding of employees, and simplification of organizational structure) increase development speed, whereas 2 approaches (implementing support systems and techniques and stimulating inter-functional coordination) decrease development speed. Two approaches (i.e., reduction of parts and components and emphasizing the customer) have no effect on development speed. Our results further show that firms developing different types of new products should use different NPD accel...