營養標示之品質揭露與膳食品質改善效果

Quality-Unfolding and Dietary-Quality Improvement Effects of Nutrition Labeling

為避免營養素攝取不當產生的健康風險，營養標示早已是許多國家公共資訊系統的一部分。關注營養標示各方效果的研究源源不斷，然多屬對消費者知覺及態度等心理層新法實施效果評估方面的探討，對於消費者知覺如何調整，進而影響其購買行為則未有定論。故本研究旨在發展營養標示資訊對消費決策影響之一般性理論模型，以Lancaster的特徵分析法為軸，另再參考Zarkin與Anderson（1992）以及Love等人（1995）的概念模型架構，本文将營養標示資訊引入食品消費決策，並建構一個一般化的理論模型。研究將營養素拆解成較健康及較不健康兩類，並深入探討營養標示資訊如何透過對消費者知覺品質的影響，進而造成購買行為的變化，產生品質揭露及膳食品質改善效果。由推論分析得知，在強制性（全面性）的規範效力下，消費者會調整其實際的最適購買組合；而自願性規範環境下，實際品質較知覺品質為差的廠商會選擇不標示，造成消費者因品質資訊不完全而無法達到真正的最適購買組合，因而導致無謂的福利損失。

Nutrition labels have been part of the public information system of different countries to avoid the health risk associated with inadequate nutrient intake. Many researchers had examined consumers' perceptions and attitudes toward nutrition labels, but none has explained how the adjustment of their psychological perception on nutrition content induced changing in purchase behavior. Following Lancaster's model of characteristics and the conceptual model of Zarkin and Anderson (1992) and Love et al. (1995), this paper constructs a generalized theoretical model that introducing nutrition label information into food consumption decision problem. By differentiating nutrients into more healthier and less health characteristics, we carefully analyze how nutrition label information can influence consumers' perceived quality and then change their purchase behaviors. We further decompose the effect to be a quality-unfolding effect and a dietary-quality-improvement effect. Another important aspect to analyze the economic effects of nutrition label information is the validity of regulations. We conclude that when the regulations on nutrition labeling are mandatory, consumers are capable of obtaining their real optimal product combination via adjusting their purchasing decision. In contrast, when facing the voluntary regulation environment, producers of over-perceived quality would not provide nutrition labels for their products. Thus, consumers could not have their own optimal product combination because of incomplete quality information. Such situation may cause some deadweight loss.