Which sampling approach is based on subjective selection of sampling locations at a site, using historical information, visual inspection, and best professional judgment to identify contaminants?

Which sampling approach is based on subjective selection of sampling locations at a site, using historical information, visual inspection, and best professional judgment to identify contaminants?

• A. Random sampling
• B. Judgmental sampling
• C. Systematic sampling
• D. Stratified sampling

Answer: (B)

Judgmental sampling is the approach where sampling locations are chosen based on the investigator’s knowledge, experience, and expectations about where contaminants are likely to be found. It uses historical information, visual inspection, and best professional judgment to target areas that are most probable hotspots. This is a purposeful, non-random method designed to efficiently identify contaminants by focusing on sites with the greatest prior evidence of problems or obvious indicators. It’s particularly useful when prior data or site features strongly suggest where issues will be, allowing quick, cost-effective characterization. However, because it relies on subjective judgment, it can introduce bias and may not fully represent the entire site, so findings should be interpreted with that limitation in mind. Other sampling approaches—random sampling that uses chance to select locations, systematic sampling that follows a regular pattern, and stratified sampling that divides the site into subareas and samples within them—emphasize representativeness and statistical inferences rather than targeted investigation based on expert judgment.

Judgmental sampling is the approach where sampling locations are chosen based on the investigator’s knowledge, experience, and expectations about where contaminants are likely to be found. It uses historical information, visual inspection, and best professional judgment to target areas that are most probable hotspots. This is a purposeful, non-random method designed to efficiently identify contaminants by focusing on sites with the greatest prior evidence of problems or obvious indicators. It’s particularly useful when prior data or site features strongly suggest where issues will be, allowing quick, cost-effective characterization. However, because it relies on subjective judgment, it can introduce bias and may not fully represent the entire site, so findings should be interpreted with that limitation in mind. Other sampling approaches—random sampling that uses chance to select locations, systematic sampling that follows a regular pattern, and stratified sampling that divides the site into subareas and samples within them—emphasize representativeness and statistical inferences rather than targeted investigation based on expert judgment.