National Center for Ecological Analysis and Synthesis
Meta-analysis, interaction strength and effect size: application of biological models to the synthesis of experimental data
Workshop III
May 15-19, 1997


Over the past year, the Meta-Analysis working group has met three times at NCEAS: July 1996, January 1997 and, most recently, May 1997. One of NCEAS's missions is the synthesis of ecological data to resolve ecological questions and improve ecological theory. Meta-analysis is designed to guide the quantitative synthesis of experimental data, and thus may play a central role in many of the future activities of NCEAS. Our working group is focused on helping guide future applications of meta-analytic procedures and influence future research into meta-analytic techniques.

The first workshop focused on general discussion of meta-analysis, and emphasized the need to 1) define appropriate metrics of effect size that are explicitly linked to ecological models and experimental designs; 2) determine appropriate estimators of these metrics and their general statistical properties; and 3) perform meta-analyses using existing data from experimental studies to highlight the application (and limitation) of meta-analytic approaches in ecology. At the conclusion of the first workshop, eight focal groups were established. The second workshop focused on data extraction and analysis of several large datasets being used by the focal groups. The third workshop focused on data analysis and writing. Ecology has approved (in concept) our proposal to publish a Special Feature highlighting the findings of this working group, and our third meeting was specifically designed to define the Special Feature and to begin writing those contributions. We envision nine papers that will be submitted for consideration by Ecology:

  1. Conducting a meta-analysis: choosing the appropriate metric for the question. (Lead author: Osenberg/Sarnelle)
  2. Conducting a meta-analysis: study selection and data extraction (Lead author: Curtis)
  3. Conducting a meta-analysis: statistical considerations (Lead author: Hedges/Gurevitch).
  4. The meta-analysis of response ratios in experimental ecology (Lead author: Hedges/Gurevitch/Curtis)
  5. Non-independence among studies: effects of phylogenetics and laboratories (Lead author: Petraitis/Dunham/Curtis)
  6. The role of ecological theory in meta-analysis. (Lead author: Holt)
  7. Plant competition across productivity gradients. (Lead author: Goldberg/Rajaniemi)
  8. Selection criteria: examples from five meta-analyses of stream predation experiments (Englund/Sarnelle)
  9. Meta-analytical lessons from marine nutrient enrichment studies (Lead author: Downing)

Participants in attendance:

Peter Curtis, Ohio State University
John Downing, Iowa State University
Arthur Dunham, University of Pennsylvania
Goran Englund, University of Umeå and UC Santa Barbara
Jessica Gurevitch, SUNY, Stony Brook
Craig Osenberg, University of Florida (Workshop Coordinator)
Peter Petraitis, University of Pennsylvania
Tara Rajaniemi, University of Michigan
Orlando Sarnelle, University of California, Santa Barbara (NCEAS Post-doctoral Fellow)
Allan Stewart-Oaten, University of California, Santa Barbara

Participants unable to attend:
Scott Cooper, University of California, Santa Barbara
Deborah Goldberg, University of Michigan
Larry Hedges, University of Chicago
David Hinkley, University of California, Santa Barbara
Robert Holt, University of Kansas