According to the report from World Health Organization, 35.3 million people in the world are currently infected with HIV and 7.6 million of people died of cancer because of the incurable diseases regarding to the immaturity of the medical technology. Because of the crucial importance of medical science contributes to the wellbeing of society, even a tiny error in it will be dreadful to the whole society. But unfortunately, as being reported from the article Lies, Damned Lies, and Medical Science, that indeed the majority of medical research, which up to 90% of the published works, are incorrect in terms of misleading, exaggerated and flat-out-wrong. This article is written by David H. Freedman as a summarization of Dr. Ioannidis' researches. In this article, it contains arguments through areas of knowledges of mathematics, which includes statistics needed when collecting data for his researches and retesting the incorrect researches he collected. It also contains natural sciences which includes biology and chemistry used when investigating and testing researches. In addition, it also has ethic argument that researchers should not lie in their researches because of the potential of hurting other people in the society. Based on the areas of knowledge he had, he analyzed and categorized his arguments through reason, sense perception, imagination, memory and languages from ways of knowings.
To answer the question that why the majority of medical researches are flawed, Dr. Ioannidis demonstrated it by drawing his past years researches which is a mix of the study of mathematics and natural sciences. I summarized the main strong arguments from the article here. The first argument is mathematics based saying that researches are wrong because of the lack of case data. So the researches are largely based on a small number of cases which the statistic date are wrong and lead the research to be biased.