Citations often report things incorrectly

Of the literature Sanz-Martín surveyed, she found that just under half of publications cited papers incorrectly. Some papers misinterpreted their sources, while others cited irrelevant papers or referred to papers selectively in order to fit the author's argument. Sanz-Martín had to sift through hundreds of papers in minute detail. It was also a challenge on a personal level, she says, because "criticising the others' work is very difficult". For completeness, she and her colleagues also analysed papers that they themselves had written on jellyfish. They found exactly the same citation mistakes.

Oddly enough a reluctance to criticise is not something I've witnessed much.

Mills's paper was a review, in which she questioned whether there was a global trend in jellification. Her answer was not a definitive "yes" or "no", so she framed her title as a question: "Are populations increasing globally in response to changing ocean conditions?" Many of the scientists who went on to cite her work seem to have assumed that her answer to that question was a firm "yes". "It didn't occur to me that by posing it as a question, and inviting people to make their own conclusions, that they wouldn't read it carefully," says Mills.

The sheer scale of the literature that scientists have to get to grips with could be one cause, Sanz-Martín says. "It is very difficult to handle all this information and also to be balanced," she says.

Furthermore, scientists need to compete for research funding, and this puts pressure on them to be bolder in their claims than they might otherwise be. "You need to have a very good reason to do research and to gain funding," Sanz-Martín says. "You need to get funding and you need to publish a certain amount of papers every year."
http://www.bbc.com/earth/story/20160905-are-swarms-of-jellyfish-taking-over-the-ocean