Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Industrial and Manufacturing Systems Engineering


The simulated plant-record (SPR) model was applied to unaged data extracted from computer generated accounts of aged data with known life characteristics. SPR reflected the property's life characteristics when all property had the same life characteristics. For property with a trend in vintage lives, SPR detected the trend but also exhibited idiosyncrasies. For example, the model indicated high mode curves with low average service lives (ASLs) or curves with mode at the origin and high ASLs. In some accounts, both high mode and origin moded curves were indicated depending upon the test band. SPR did not indicate a unique curve for some test bands. These idiosyncrasies were explained by reference to the underlying algorithm of the model, and the conditions under which these idiosyncrasies occur were defined;When accounts of unaged and aged data with identical life characteristics were examined, the survivor curves indicated by SPR differed from those indicated by the retirement rate (RR) actuarial model unless all property in the account had the same life characteristics. The difference was explained using survivor curves calculated by the multiple original group (MOG) actuarial model;The impact of the difference in survivor curves indicated by the SPR and RR models was investigated by comparing the depreciation calculated using these curves. Neither model's survivor curves produced annual or accumulated depreciation matching that calculated by the straight-line method, vintage group procedure using the property's known life characteristics. The annual accrual comparisons indicate that the SPR model is a more reliable indicator of ASL than of retirement dispersion pattern;Because of the model's biases and differing indications depending upon the test band, the pattern of installations and balances and the maximum age of the account should be considered with selecting test bands. Since the problems associated with finding an average curve for a variable life account can be avoided if depreciation is calculated by vintage, a semiactuarial model, such as computed mortality, that permits the calculation of vintage group depreciation merits investigation.



Digital Repository @ Iowa State University,

Copyright Owner

Susan Dianne Jensen



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File Size

145 pages