Abstract: Apparatus and methods relate to applying a condition decay function to a property's initial investment value to generate numerical baseline condition scores for multiple predetermined time increments, and adjusting the baseline condition scores by investment value of property structure improvements occurring during each time increment and scaled according to a statistical distribution of values of property structure improvements to peer structures. Investment values may be calculated per square foot of structure. Investment values of an investment activity may be imputed according to a statistical distribution of investment values of peer structure investment activities. Adjusted condition score values may be scaled to standardized condition score values according to a predetermined quantile shift function for a property's jurisdiction(s). Effective age of a structure may be determined from condition score values.