Degree Type


Date of Award


Degree Name

Master of Science


Veterinary Diagnostic and Production Animal Medicine


Veterinary Preventive Medicine

First Advisor

Annette M. O'Connor


Appropriate design, implementation, and analysis of any particular study design are paramount to making accurate causal or association measures. Proper design and reporting are essential for making valid inference therefore in-depth training in observational study design is critical for epidemiologists. The purpose of this thesis was to illustrate and teach the application of study designs. Although seemingly disparate investigations, the thesis results illustrate the existing confusion in the design and reporting of case-control studies and randomized controlled trials (RCT) in veterinary science. The thesis results show the need for thoughtful design considerations a priori to beginning any research study and purposeful reporting. The approach employed for the thesis was to review the conduct and reporting of two study designs with veterinary applications so as to understand their conduct, advantages, and limitations. The main chapters are: 1) a systematic review with meta-analyses of RCTs looking at treatments for infectious bovine respiratory disease, and 2) a survey assessing published case-control manuscripts in the veterinary science. The results of the chapters illustrate that many studies are conducted and/or reported without understanding of the key aspects of study design. For example, for the study of RCTs, many of the controlled trials conducted failed to report key design features such as randomization and blinding. Similarly, the survey of case-control studies documented that many authors either failed to understand this design or simply misnamed the design as a cohort or cross-sectional. For the individual topics studied within each chapter, the results have implications for treatment of animals and how we study the cause of disease. However, taken as a whole, the work of the thesis documents a need for a solid understanding of the conduct and reporting of observational study design to ensure maximum value is obtained from them.


Copyright Owner

Jonah Nelson Cullen



File Format


File Size

135 pages