Short communication: On recognizing the proper experimental unit in animal studies in the dairy sciences.
Sound design of experiments combined with proper implementation of appropriate statistical methods for data analysis are critical for producing meaningful scientific results that are both replicable and reproducible. This communication addresses specific aspects of design and analysis of experiments relevant to the dairy sciences and, in so doing, responds to recent concerns raised in a letter to the editor of the Journal of Dairy Science regarding journal policy for research publications on pen-based animal studies. We further elaborate on points raised, rectify interpretation of important concepts, and show how aspects of statistical inference and elicitation of research conclusions are affected.
Department of Statistics, Kansas State University, Manhattan 66506. Electronic address: nbello@ksu.edu.
Nora M
NM
Bello
USDA, Agricultural Research Service, Beltsville, MD 20705.
Matthew
M
Kramer
Department of Animal Science, Michigan State University, East Lansing 48824.
Robert J
RJ
Tempelman
Department of Statistics, University of Nebraska, Lincoln 68583.
Walter W
WW
Stroup
Department of Animal Sciences, The Ohio State University, Columbus 43210.
Normand R
NR
St-Pierre
Department of Statistics, Purdue University, West Lafayette, IN 47907.
Bruce A
BA
Craig
National Agricultural Statistics Service, Washington, DC 20250.
Linda J
LJ
Young
Agricultural Statistics Laboratory, University of Arkansas, Fayetteville 72701.
Edward E
EE
Gbur
D000818:Animals; D001699:Biometry; D003142:Communication; D057766:Policy; D012106:Research
experimental unit; hierarchical data structure; observational unit; pen; replication