Some projects assessing the quality of published literature in different fields of veterinary medicine have revealed substantial deficits in reported studies, even those in very reputable peer-reviewed journals (Cockroft et al. 2007, Kastelic et al. 2006)! When you read a paper, you should keep this in mind, as you may find conclusions formulated by authors that are based on weak, or even no, scientific data. Other papers may report information generated using inappropriate study designs (see The level of evidence) which therefore invalidate the conclusions. As we’re on the topic of EBVM, we can see there is actually evidence for this: reviews on veterinary topics reveal that, for instance, less than a quarter of papers are good enough to enable us to draw sound conclusions from them (Simoneit et al. 2011)!
This chapter focuses on appraising the quality of scientific literature. When appraising other information sources, it is important to be even more critical. Consider the origin of the information, who wrote it, and why? Some of the limitations of internet searching are discussed in ASK, but the principles discussed in this chapter can also be applied when reading other sources of information.