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Prescriptive Specifications
© 1997, 1998 Streamline Publications
Two types of specifications are
commonly used in contracts dealing with landscape and revegetation projects:
Performance and Prescription. A performance spec merely states what
the final outcome of the project should be, e.g., ...perennial turfgrass
cover, three deciduous trees per one thousand square yards, drainage that meets
all current regulations and industry standards.... Such a specification leaves the method
used by the contractor up to the contractor. Successful completion of work will
be judged on the basis of the project's outcome. Prescriptive specifications, on the
other hand, tell the contractor exactly what to do and how to do it. He will
have fulfilled his contract if he plants three prescribed trees at prescribed
spots in holes of a prescribed depth; a 100 pounds of seed X and 50 pounds of
fertilizer Y using equipment Z. Nothing has to actually grow in order
to meet the prescription. Caltrans, however, uses its projects with prescribed
specs as a laboratory for monitored experiments. The prescriptions are not
simply boilerplate generated by a government computer. Rather, they are
carefully designed plans that are closely watched and evaluated by the Caltrans
researchers. Conclusions are drawn and new methods and recommendations are
devised. For other purchasers of landscaping
services there is often a lack of qualified inspectors to evaluate prescribed
methods. In this case a better approach is to use performance-oriented specs.
The contractor is left to his own devices but must deliver a finished, growing,
healthy landscape, not just go through the motions. With performance specs, the
contractor becomes the researcher and is free to develop cost-effective methods
that benefit the industry. Check with
Albright for answers that
make sense for your clients.
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