廣告量對品牌態度與購買率之長期影響

The Longitudinal Effects of Advertising Expenditure on Consumers’ Attitudes to Brands and Purchase Rates

本研究採用國內兩大資料庫的十年長期資料，探討廣告量占比對消費者的品牌態度與購買率的影響，逐一檢視廣告量函數的形狀、廣告的階層效果與遞延效果，並採用panel data 分析法進行分析。研究結果發現，廣告量占比的確對常購品與選購品的品牌態度與購買率都有正向的影響。在廣告量占比對購買率的函數形狀部份，食品類與飲料類產品呈現正向相關段的concave 函數，而家庭用品類與選購品則為線性函數。廣告階層效果的研究結果顯示，購買率在常購品類中的食品類對品牌態度為部份中介效果，在飲料類為一完全中介變數；而在選購品中，消費者的品牌態度在電器機車類對購買率有部份中介效果，在金融產品類呈現出完全中介效果。透過九年的資料分析廣告量的遞延效果可發現，前期的廣告效果透過影響消費者前期品牌態度或者是前期購買率，進而間接地影響本期的購買率或本期的品牌態度，說明廣告的展露會隨著時間的經過，轉化成為公司的一項無形資產，行銷經理需更注意廣告支出的遞延效果與長期累積效果。

The current study employed two datasets, Rainmaker XKM’s ad expenditure report and Eastern Integrated Consumer Profile (E-ICP) to investigate the shape of “ad share-brand attitude” function and “ad share-purchase rate” function, and explored the mediating effects of brand attitude and sales share based on the hierarchy of effects of ads, and the cumulated effects of ads. Panel data analysis was used since it could avoid the estimation bias from single cross-sectional or timeseries analysis only. The findings revealed that the shape of ad share-purchase rate function reflected the positive part of a concave curve in food and beverage, but linear in other product categories. The results also illustrated a partial mediation effect of purchase rate on brand attitude in food products, and a full mediation effect in beverage. In the category of shopping goods, consumers’ brand attitudes had a partial mediating effect on purchase rate in electronics, and a full mediating effect in financial products, such as credit cards, insurances, and saving accounts. Ad investment in the previous period was transferred into the purchase rate or brand attitude of the previous period, and then further influenced the purchase in the current period. Therefore, marketers should focus more on the long run benefits of ad investment and maintain the cumulated effect.