部分調整行為之估價平滑－－以地價基準地重估價為例

Appraisal Smoothing of Partial Adjustment Behavior: Evidence from Revaluation of Land Value Benchmark

相較於以往探討估價平滑之文獻，多採總體層級（aggregate level）方式探討，藉估值指數變異數小於成交價格指數變異數進行平滑之研究；本文則以個體層級為出發點，蒐集全國各直轄市、縣（市）地價基準地之重估價資料，觀察估價平滑與部分調整行為之情形。首先參考Quan and Quigley（1991）提出之理性調整模型分析市場價格參考點與當期估值之關係，探討估價人員是否因信心不足採取較保守的部分調整更新策略，以至於估價平滑現象產生。研究結果發現，整體估價之信心參數為0.59，相對大於前次估值之權重0.399，具有部分調整現象。其次，就市場信心參數較低之臺中市，不同估價方法估值標準差之比例每增加1%，信心程度將減少0.11。估價年資每提高一年，信心程度將增加0.0219。代表基準地相較於一般基準地，信心程度增加0.74。 Opposed to past literature studying the appraisal smoothing, which discussed the reduced volatility and/or lagging in the appraisal based index compared to a contemporaneous transaction based index from aggregate level, this paper observed the appraisal smoothing caused by partial adjustment from individual level using revaluation data on land value benchmark nationwide. By reference of rational adjustment model proposed by Quan and Quigley (1991) analyzing the relationship between the market transaction reference point and contemporaneous appraisal, this paper researched whether appraisal smoothing occur or not due to partial adjustment strategy for that valuers are lack of confidence and being conservative. The empirical results showed that the overall appraisal confidence factor is 0.59, which is greater than the weight, 0.399, of the prior appraisal. The partial adjustment behavior existed. Moreover, for Taichung city, whose market confidence parameter is lower, the confidence factor decreased 0.11 when the standard deviation ratio of different appraisal from approaches increased 1%. The confidence factor increased 0.0219 if the appraisal career increased one year. The confidence factor increased 0.74 from the representative land value benchmark opposed to the base, ordinary land value benchmark.