多財貨雙界二元選擇條件評估起始點偏誤檢定與校正模型之建構──改善三高危險因子對心血管疾病願付價值之評估

Model for Correcting Starting-Point Bias of Multiple Goods under Double-Bounded Dichotomous Choice CV Data: Evaluation of WTP for Controlling Three Major Risk Factors of Cardiovascular Disease

本研究建構一個雙界二元選擇評估多個有相關性財貨起始點偏誤的檢定與校正模型，此一模型改良過去只針對單一財貨未考量財貨間的替代／互補性的單界或雙界二元選擇起始點偏誤模型。並使用一套長期追蹤竹東及朴子地區心臟血管疾病之資料，比較有無考量危險因子之相關性與有無校正起始點偏誤，改善高血壓、高血脂及糖尿病三危險因子願付價值的差異。結果顯示，考量因子間之相關性，則改善心血管疾病三高因子平均的每年每人估計願付價值均比未考量時來得低。同樣的，校正雙界二元起始點偏誤，每年每人改善三危險因子之估計效益，也比未校正時來得低。依此，本文所建構之檢定與校正起始點偏誤且考量三危險因子相關係之模型，所得到的每人每年改善三危險因子之估計效益為174,667元，反之，如果未進行起始點偏誤也未考量因子間的相關係，則估計效益為335,657元，二者相差二倍有餘。

This study constructs a model to account for the starting-point bias of multiple goods and services under the double-bounded dichotomous choice contingent valuation experiment. A set of data of cardiovascular disease risk factor two-township study (CVDFACTS) is adopted for the willingness to pay comparison between models for controlling hypertension, hyperlipemia, and diabetes three major causes of cardiovascular disease risk factors. The results show that the relationship exists among these three factors. As such, the benefit for controlling these factors with the adjustment of starting-point bias and accounting for the relationship among factors is NT 174,667 per capita annually. On the contrary, the benefit without the adjustment of starting-point bias and not accounting for the relationship among factors is NT 335,657 per person per year. This demonstrates that the total benefit will be biased upward while no concern is accounted for the evaluation of multiple goods.