選項集合在隨機效用模型應用之關鍵性－以沿海溼地遊憩價值之評估為例

The Impact of Choice Set Definition on Random Utility Models: Taiwanese Coastal Wetland Valuation as an Example

曾偉君(Wei-Chun Tseng) ； 黃俊燁(Juin-Yie Huang)

《經濟論文叢刊》 34卷2期 (2006/06) Pp. 209-243

https://doi.org/10.6277/ter.2006.342.3

摘要

本文探討選項集合設定對遊憩地點決策的影響，四種選項集合設定包括：(1)調查中所有的地點，(2)消費者聽過的地點，(3)消費者去過的地點，(4)某段距離以內的地點。資料來自在19個台灣濕地，對隨機抽取的受訪者進行的問卷調查。估計結果顯示，不論是羅吉特模型，或是混合式羅吉特模型，參數估計值及福利值，都受到選項集合設定的顯著影響，而且一般而言，較大之選項集合產生較小之福利值。僅管放寬獨立於無關聯選項的假設，而且允許個人化參數之估計，混合式羅吉特模型，並沒有緩解選項集合設定，對效益估計值的衝擊。

關鍵字

隨機效用模型 ； 選項集合 ； 羅吉特模型 ； 混合式羅吉特模型

並列摘要

This paper discusses alternative criteria for defining the choice set in the analysis of recreational site choice decisions. Four definitions are considered: 1) all available sites compiled by the researcher, 2) sites known by individuals, 3) sites previously visited by individuals, and 4) sites grouped by distance from individual residence. A survey of randomly sampled visitors was conducted at 19 wetland sites in Taiwan. The recreational trip choices to 19 wetland sites are analyzed using the conditional logit (CL) and mixed logit (MXL) models under each of the four choice set definitions. The estimation results show that regardless of choice model, both parameter estimates and welfare measures are significantly affected by the definition of choice sets and in general a smaller measure of welfare results from a larger choice set. Despite the relaxation of the independence of irrelevant alternative (I.I.A.) hypothesis and individual specific parameter estimates, the flexible mixed logit model does not alleviate the impact of choice set definition on welfare measures.

並列關鍵字

random utility models ； choice set ； conditional logit model ； mixed logit model

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