An approach to identify bias in scent detection dog testing

Numerous scientific studies show the increasing importance of trained scent detection dogs in a wide field of application. Methods used for testing scent detection dogs are heterogeneous and therefore susceptible for potential bias. Nevertheless, no accepted quality standards or adequate guidelines for performing scent studies and testing dogs have been published in the peer-reviewed literature yet. Therefore the objective of this systematic review was to evaluate publications on scent dog studies including test procedures and to identify methodological issues that could potentially bias or confound the study outcome. Using the databases Pubmed (www.pubmed.gov) and CAB (http://ovidsp.tx.ovid.com), a systematic literature research was conducted on 23th July 2015 to find studies on scent detection work in dogs. Additional studies were recruited through a supplementary hand search. After a specific exclusion process, 54 studies were left for the final evaluation. Factors potentially influencing the outcome of scent detection studies with trained dogs were identified. We critically analyzed how the authors discussed potential flaws. Finally, we were able to condense the information into a best practice standard for scent dog studies regarding the target odour, type of scent detection task and experimental set-up, samples used for training and testing, test design, dog trainer and training procedure and used dog breeds.