USGS - science for a changing world

Northern Prairie Wildlife Research Center

  Home About NPWRC Our Science Staff Employment Contacts Common Questions About the Site

The Importance of Replication in Wildlife Research

Douglas H. Johnson

Abstract:  Wildlife ecology and management studies have been widely criticized for deficiencies in design or analysis. Manipulative experiments-with controls, randomization, and replication in space and time-provide powerful ways of learning about natural systems and establishing causal relationships, but such studies are rare in our field. Observational studies and sample surveys are more common; they also require appropriate design and analysis. More important than the design and analysis of individual studies is metareplication: replication of entire studies. Similar conclusions obtained from studies of the same phenomenon conducted under widely differing conditions will give us greater confidence in the generality of those findings than would any single study, however well designed and executed.

Key words:  control, experiment, metareplication, observational study, pseudoreplication, randomization, replication, sample survey, science

This resource is based on the following resource (Northern Prairie Publication 1190):

Johnson, Douglas H.  2002.  The importance of replication in wildlife research.  Journal of Wildlife Management 66(4):919-932.

This resource should be cited as:

Johnson, Douglas H.  2002.  The importance of replication in wildlife research.  Journal of Wildlife Management 66(4):919-932.  Jamestown, ND: Northern Prairie Wildlife Research Center Online.  (Version 14OCT2004).

Table of Contents


I am grateful to the many statisticians and biologists who have taught me so much as teachers, colleagues, or students. B. R. Euliss helped prepare the manuscript. Special thanks for valuable comments on this manuscript to D. R. Anderson, L. A. Brennan, K. P. Burnham, L. L. Eberhardt, S. H. Hurlbert, W. P. Kuvlesky, Jr., J. D. Nichols, M. R. Riggs, G. A. Sargeant, A. Stewart-Oaten, and an anonymous referee, all of whom nonetheless deserve to be held blameless for remaining faults. Thanks also to L. A. Brennan for the invitation to write the paper.

Douglas H. Johnson, U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, ND 58401, USA; e-mail:

Downloading Instructions -- Instructions on downloading and extracting files from this site.
(Download) ( 69K) -- The Importance of Replication in Wildlife Research
Installation: Extract all files and open index.htm in a web browser.

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: Webmaster
Page Last Modified: Saturday, 02-Feb-2013 06:03:10 EST
Sioux Falls, SD [sdww54]