Keywords: distortion, tunnel vision, bias, citations, citation bias, falsification, knowledge development, hygiene hypothesis, diesel emissions, swimming in chlorinated water

“Standing on one shoulder: citation bias in the epidemiological literature”

Newton once wrote: “If I have seen further, it is by standing on the shoulders of giants.” Science can make progress by building on earlier research. Citation analyses can show which research is being built on. If only positive studies that confirm a hypothesis are quoted, and negative studies that undermine the same hypothesis are ignored, we experience citation bias. This bias can lead to the development of knowledge being distorted, unnecessary research being carried out and incorrect decisions being made. This dissertation investigated whether there is selective quoting within the epidemiological literature, and specifically whether there is citation bias. This appears to be the case; in particular, positive studies seem to prefer to cite other positive studies, while negative studies have no publications for positive or negative studies.