英文文献：The Measurement Of Depreciation In The Cost Approach To Valuation-在成本法估价法中折旧的计量
英文文献作者：Olusegun Adebayo OGUNBA,Ismail Kolawole BELLO
英文文献摘要：
PURPOSE: It has been an embarrassment to the valuation profession where it found that its professional practices have been a little more than educated guesses. This has been particularly true in the estimation of depreciation in the use of the cost method for valuing land and buildings and plants and machinery. The study set out to investigate current models adopted for the measurement of depreciation in Nigeria, examine the patterns of depreciation for residential properties in the study area and evaluate the conformity of the identified models to depreciation patterns. These were done with a view to improving cost valuation practice.METHODS FOLLOWED: Questionnaires were administered on a cross sectional survey of 154 valuation firms across Southwestern Nigeria to address the three questions.FINDINGS: The study found that current models adopted by valuers for the measurement of depreciation of residential buildings were the estimated percentage model and age life models. However, the pattern of depreciation was found to follow an S shape. An analysis of the models usually adopted vis-a-vis the S shaped depreciation pattern using the Student t-test showed no significant relationship. This showed that the use of depreciation in the cost method of valuation has accuracy deficiencies. Other tests demonstrated that depreciation measurement is user-friendly but inconsistent and incapable of separating depreciation components.THEORETICAL AND PRACTICAL IMPLICATIONS: The paper has discomforting implications for the reliability of professionally prepared valuation estimates for residential property and calls for urgent corrective action along the lines of S shaped depreciation.ORIGINALITY: The paper expands and improves on earlier depreciation measurement studies which were restricted in terms of geographical scope and methodology. Keywords: cost valuation, depreciation

目的:对估值专业人士来说，这一直是一个尴尬，因为他们发现，自己的专业实践已经超过了有根据的猜测。在使用对土地和建筑物以及厂房和机器估价的成本法进行折旧估计时，尤其如此。该研究旨在调查尼日利亚目前用于折旧测量的模型，检查研究区域内住宅的折旧模式，并评估所识别的模型与折旧模式的一致性。这样做的目的是为了改进成本估价的做法。方法如下:通过对尼日利亚西南部154家估值公司的横断面调查，对三个问题进行问卷调查。研究结果:目前评估人员采用的住宅折旧模型为估计百分比模型和年龄寿命模型。然而，折旧的模式被发现是遵循一个S型。使用学生t检验对通常采用的模型与S型折旧模式进行分析，结果显示没有显著关系。这说明采用折旧法进行成本计价存在准确性不足。其他检验表明，折旧测量是友好的，但不一致，无法分离折旧成分。理论和实践意义:本文对专业编制的住宅地产估值估算的可靠性提出了令人不安的启示，并呼吁采取类似S型折旧的紧急纠正行动。创新性:对以往的折旧计量研究在地域范围和方法上的局限进行了扩展和改进。关键词:成本评估，折旧