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Site Status Categories and Design Impacts
Site Status Categories
o Impact on Analysis
- Sites selected may not be visited (not needed):
- Generally sites in over sample, no impact.
- Target Population Sites:
- Basis for all population estimates on characteristics of target population.
- Non-Target Stream Sites:
- Site visit determines non-target site; e.g., non-wadeable stream, intermittent stream, no channel present, reservoir, etc.
- Impacts estimate of "size" or "extent" of target population.
- Physically Inaccessible Stream Sites:
- Reasons; Safety concerns to access or sample site, Remoteness of sample site.
- Impacts; Potential bias due to different characteristics at those sites than at target sites that are accessible, No impact on target population extent estimate.
- Access Denied Sites:
- Landowner may deny physical access to site for sampling.
- Impacts: Potential bias in sites where landowner denies access compared to characteristics at sites where access is granted.
- Other Non-Sampled Sites:
- If missing at random: Estimate extent or assume target population missing at random has same characteristics as sampled target population.