Advertising expenditure There have been many attempts to correlate industry types, product characteristics, geographical locations and other characteristics with advertising -to-sales ratios. However, in most cases advertising still remains a mystery Since neither empirically nor theoretically can we explain why different firms spend different amounts on advertisingAdvertising Expenditure • There have been many attempts to correlate industry types, product characteristics, geographical locations, and other characteristics with advertising-to-sales ratios. However, in most cases advertising still remains a mystery since neither empirically nor theoretically can we explain why different firms spend different amounts on advertising