Selecting Assessment End Points (Cont.)

a. Closeness of correspondence to the assessment end point: This attribute

refers to the extent to which the measurement end point is representative of,

correlated with, or applicable to the assessment end point. If there is no

association between a measurement end point (e.g., a study that may have

been performed for some other purpose) and the assessment end point of

interest, then that study should not be used to evaluate the stated

assessment end point.

b. Site specificity: This attribute relates to the extent to which data, media,

species, environmental conditions, and habitat types used in the study

design reflect the site of interest.

c. Stressor specificity: This attribute relates to the degree to which the

measurement end point is associated with the specific stressor(s) of

concern. (Stressors might include a particular chemical, waste, or physical

alterations.) Some measurement end points may respond to a broad range of

stressors so that it is difficult to interpret results with regard to the stressor

of concern, while other measurement end points are more specific to a

particular stressor.

d. Availability of an objective measure for judging environmental harm: This

attribute relates to the ability to judge results of the study against well-

accepted standards, criteria, or objective measures. Examples of objective

standards or measures for judgment might include ambient WQC, sediment

quality guidelines, biological indices, and toxicity or exposure thresholds

recognized by the scientific or regulatory community as measures of

environmental harm.

e. Sensitivity of the measurement end point for detecting changes: This

attribute relates to the ability to detect a response in the measurement end

point. The sensitivity of the measurement end point may be affected by

natural or analytical variability.

f. Quantitative: The attribute relates to the degree to which numbers can be

used to describe the magnitude of response of the measurement end point to

the stressor. Some measurement end points may yield qualitative or

hierarchical results, while others may be more quantitative.

g. Correlation of stressor to response: This attribute relates to the degree to

which a correlation is observed between levels of exposure to a stressor and

levels of response, and the strength of that correlation.

h. Use of a standard method: The extent to which the study follows specific

protocols recommended by a recognized scientific authority for conducting

the method correctly. Examples of standard methods are study designs or

chemical measures published in the Federal Register or the Code of Federal

Regulations, developed by the American Society for Testing and Materials

(ASTM), or repeatedly published in the peer-reviewed scientific literature.

Chapter 2 Problem Formulation