Habitat restoration is sometimes a surrogate for ecosystem restoration, either because the habitat is considered an integrator for multiple ecosystem processes, or because it is a relatively easy way to go. Habitat evaluation can be used in assessing project outputs for species or communities for a number of purposes. In addition, formats of habitat evaluation can be used with other components besides biotic.
The Habitat Evaluation Procedures (HEP) were developed by the U.S. Fish and Wildlife Service (FWS) to quantify the effects of water resource projects on fish and wildlife. Development occurred jointly with other Federal agencies, including the Corps of Engineers. The FWS Ecological Services Manuals (ESM) 100, 101, and 102 describe the Procedures in some detail.
HEP has been used and accused over the years. It remains a very flexible framework for simple quantification of biological resources.
In this section, we provide several documents written to help prepare models and evaluations.
A Workshop Approach to Determining Variables for Habitat Suitability Index (HSI) Models
Template for Obtaining Review of Habitat Models
Use of Species Experts in Habitat Evaluation
A
Method to Create Simplified Versions of Existing HSI Models
A
Procedure to Modify Habitat Suitability Index Models 
The collection of published HSI models has received various levels of review and testing, from none to fairly complete. The user is responsible for determining how well the model can be expected to perform in the intended location and application. Many of the models include life history reviews and can be adjusted for use in areas other than where they were constructed, and so provide ideas for other users.
A
report by Terrell and Carpenter (1997) "Selected Habitat Suitability Index
model evaluations" 
critiques
a large number of model tests. "Concepts
and Constraints of Habitat Model Testing" (Schamberger and O'Neil 1986)
is a short introductory paper to testing and model construction. 
Illustrations of selected model tests are provided below. Very often, the model test document also provides a new or revised model, as well.
Wildlife
Species Richness in Shelterbelts: Test of a Habitat Model 
Validating
a Habitat Evaluation Method for Predicting Avian Richness 