General Principles, Designs, and Statistical Analyses in Experimental Animal Studies

Research using animals contributes significantly to many research and development studies, especially in the biomedical field. Within the scope of the study, conducting animal experiments in accordance with scientific principles and ensuring the ethical use and welfare of animals are issues that should be taken into consideration. In this context, the scientific contribution to be achieved by conducting these studies in line with scientific and ethical principles will be directly proportional. In many studies, while investigating the biological significance, it is seen that the effects of many factors are ignored, the answer to the biological question is investigated with simple experimental designs, or the accurate statistical analyses are not chosen. Therefore, in this study, the principles that a researcher planning an animal study should follow within the scope of the research (animal ethics, 3R, and other R rules, determination of sample size, randomization, and blinding) are briefly mentioned. Then, completely randomized design, regression design, split-unit design, hierarchical (nested) design, mixed effects design, and appropriate statistical analyses for these designs, which are thought to be useful in these studies, are discussed. It is thought that this review will be useful as it contains important summative information that will guide all researchers in planning animal studies accurately and quickly.