Does Generic Advertising Warp Demand Curvature?

本文從理論與實證分析的角度探討一般性廣告對需求曲線的影響，進而推論當市場清結時，均衡價格與數量即可得知。有別於之前文獻只討論線性需求函數，本文著重廣告對非線性需求函數的影響。我們假設廣告會造成非線性需求曲線的曲度擴大，即當市場價格上升時，廣告會緩和消費需求的減少﹔反之當市場價格下降時，廣告會加強消費需求的增加。實證分析以美國牛肉市場為例，期間從1976 至1996 年。結果發現一般性廣告對美國牛肉市場需求曲線的影響符合本文假設，即需求曲線的曲度增加。此外，本文並建議若配合市場供給可模擬均衡價量，如此將可更完整與正確地評估廣告的效率性。

This paper reconsiders the impacts of generic advertising oncommodity prices induced through demand effects. Rather thanconsidering a simple demand shift, we consider the possibility thatadvertising leads to a change in curvature of the demand curve. Toevaluate this possibility we consider U.S. aggregate demand for beef.Quarterly data from 1976 through 1996 is used. Based on parametrictests, we find evidence consistent with convexity in the demand curve forbeef with respect to its own price. Further, we find evidence that thedemand elasticity and the convexity of demand are affected by theintensity of generic advertising.