June 2009
Front Matter
Training
45
Differences Among Sampling Networks
•When using data from different sampling networks, it is important to consider
–The multiple sampling networks from which data were drawn for these analyses vary in their objectives and sampling and analytical methods.  Data may not always be comparable.
–Sampling, analysis, method detection limits, objectives, site characteristics, etc. have changed over time.  Care is needed in interpreting temporal and spatial trends.
•Analysts need to gather, and understand, all metadata prior to conducting analyses.