What is the difference between increasing returns to scale and economies of scale in terms of their impact on production efficiency and cost savings?

Increasing returns to scale refer to a situation where a company's output increases at a faster rate than its inputs, leading to lower average costs and higher efficiency. Economies of scale, on the other hand, occur when a company's average costs decrease as it produces more units. Both concepts result in cost savings and improved production efficiency, but increasing returns to scale focus on the relationship between output and inputs, while economies of scale focus on the relationship between production volume and costs.