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Depreciation Textbooks


The Society of Depreciation Professionals (SDP) announced the formation of the SDP Education Fund (Fund) in 2018 to further SDP’s purpose as an educational institution. The Fund will help to further the SDP’s objectives “… to promote the professional development and professional ethics of those practitioners in the field of depreciation; to collect and exchange information about depreciation engineering and analysis; to provide a national forum of programs and publications concerning depreciation.”


The views expressed in the books provided through the SDP Education Fund are those of the authors.  These opinions do not necessarily reflect the views of the Society of Depreciation Professionals.

Publications Available through the SDP Education Fund: 

  • Depreciation Systems by Frank K. Wolf and W. Chester Fitch - $50 donation
  • Iowa Engineering Experiment Station Bulletin 125, "Statistical Analyses of Industrial Property Retirements" - $35 Donation
  • Iowa Engineering Experiment Station Bulletin 155, "Depreciation of Group Properties" - $35 Donation

Publication Descriptions

Through the fund you have the opportunity to acquire three highly regarded depreciation textbooks. These publications have been out of circulation in recent years, but SDP has obtained permission from the original publishers to reproduce them for the SDP Education Fund.


Depreciation Systems by Frank K. Wolf and W. Chester Fitch is a highly regarded and widely cited textbook that covers, in detail, a range of depreciation topics, including survivor curves, net salvage concepts, depreciation systems, actuarial and simulation life analysis methods, and service life and salvage forecasting. 

Statistical Analyses of Industrial Property Retirements (Bulletin 125) by Robley Winfrey presents five methods of assembling data for constructing survivor, frequency, and probable life curves. From a study of 176 survivor curves representing different industrial property, 18 typical survivor curves and their mathematical equations were developed. The 4 origin moded (“O”) curves developed by Frank Couch are also included in the text. Curve fitting calculations using other methods (e.g., Gompertz-Makeham) are shown.

Depreciation of Group Properties (Bulletin 155) by Robley Winfrey presents methods for estimating the depreciation for groups of units. Emphasis is placed on developing, by age, the condition percent, defined as 100 times the ratio of the present depreciable value of a property to its depreciable value new. Methods of applying the condition percent formula to group property are illustrated. Normal depreciation reserve levels are calculated for each of the 18 type survivor curves, where a normal property group is defined as a nongrowing property with constant average age.


To donate to the Fund and receive a copy of the texts, please CLICK HERE


*Please Note at this time, shipping of the books is delayed due to the office being closed.


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