What factors contributed to the emergence of activity based costing in the 1980s?

The Traditional costing system used to allocate/assign overhead costs to products by using only volume based cost drivers. In fact, these traditional systems were designed decades ago when most companies manufactured a narrow range of products, and direct labour and materials were the dominant factory costs. Overheads costs were relatively small and the distortions arising from inappropriate overhead allocations were not significant. Danish Ayub