Chapter 1.3: Experimental Design and Sampling
Hopefully, many of you will have opportunities to collect data in your professional careers. This might be to monitor the conditions of a given ecosystem, test the efficacy of various treatments, or describe temporal or spatial patterns in key ecosystem characteristics. Most students who have made it through an environmental program have been trained in proper field and laboratory techniques to collect measurements. But our training in how to select observations on which to collect those measurements often falls short. As a result, there are many practicing environmental professionals who are really good at collecting data but not as good at ensuring that the data they collect can tell them what they want to know. This is where a little knowledge of experimental design can go a long way.
Experimental design is the creation of a detailed experimental plan that allows you to obtain the maximum amount of information specific to your objectives.
A sampling design lays out exactly how you will select the observations about which you make your measurements.
Background Materials:
A brief essay on the basics of experimental design:
http://liutaiomottola.com/myth/expdesig.html
Experimental design and sampling design basics:
http://stattrek.com/experiments/experimental-design.aspx?Tutorial=AP
Principles of sampling and sample design:
http://www.skillsyouneed.com/learn/sampling-sample-design.html
Guidance from the Nature Conservancy on choosing sampling designs for environmental data collection:
https://www.conservationgateway.org/ExternalLinks/Pages/guidance-choosing-samplin.aspx
The US EPA’s guidelines for choosing a sampling design. A little dense but jam packed with useful tidbits:
https://www.epa.gov/sites/production/files/2015-06/documents/g5s-final.pdf
Textbook References and Links:
Keys to help determine the appropriate statistical analysis and
data analytics summary guide for identifying the right test: http://www.dataanalytics.org.uk/Data Analysis/Statistics/choosing-your-stats-test.htm
An interactive dichotomous key to take you to the correct test: http://ccnmtl.columbia.edu/projects/seeu/dr/statistics.html
Prefer a table format of your basic statistical options? Try this link: http://www.biostathandbook.com/testchoice.html
A flow chart for selecting common statistical tests: http://abacus.bates.edu/~ganderso/biology/resources/stats_flow_chart_v2014.pdf
Downloadable data and files: NA
