Envision Models: Parametric Methodology
The Envision cost models use a parametric cost modeling methodology called Integrated Cost Estimating Relationships (ICER). An ICER is an integrated set of Cost Estimating Relationships (CER) as the name implies. A CER is, at its heart, a mathematical expression that takes one or more cost-driving (independent) parameters and calculates (dependent) costs.
Typically, the ICER methodology is used if details do not exist in a detailed assemblies or line–item database, resources and schedule are limited, or the cost output is to be used only for budgetary estimates, sensitivity analyses, trade studies, or other analyses.
Envision CER Types
Envision models can be broken down into three different types of CERs.
- Technology Based CERs: Equations calculating technology-specific construction and/or operations and maintenance cost elements.
- Fee Based or Simple CERs: Equations calculating the cost based on a fee (or unit cost) for a quantity of items or service, such as, disposal cost per ton of construction waste.
- Professional Labor CERs: Calculation of cause and effect as it relates to the parameters driving (or causing) activities and the effect on the organization of personnel conducting the activities (who is doing what).
How it Works
The mechanics are rather simple: you are presented with a list of questions (parameters) about your site. The values you enter are run through a series of equations in the CER. Once complete, you get a cost report that also includes all the calculated values for other questions (parameters) you might not have answered.
Review the report against your site conditions and project/organization details. Use adjustment parameters to tailor the estimate to your specific needs (example: cost markup factors).
Finally, provide your feedback and get online support for your estimate.
