What constitutes valid, reliable, and relevant evidence? Why is it necessary to always consider the validity, reliability, and relevance of a research study?

PArt 1
What constitutes valid, reliable, and relevant evidence? Why is it necessary to always consider the validity, reliability, and relevance of a research study? As you explain why a systematic appraisal of the evidence is necessary, consider the alternative to valid, reliable, and relevant evidence and the potential resulting outcomes. As always, provide substantive support of your views and opinions using appropriate research articles.

part 2
In 1998, Wakefield et al. reported a link between the administration of the MMR vaccine and a form of autism, igniting panic and contributing to a public health issue that continues today. Intentional or not, the research was flawed with bias. (You can read more about Wakefield’s study and fraudulent reporting here: Wakefield’s article linking MMR vaccine and autism was fraudulent.)
Ethical issues such as confirmation bias, whether intentional or unintentional, hold a significant impact for consumers of research. How can a manager or healthcare team work to prevent confirmation bias in EBM? As always, provide substantive support of your views and opinions using appropriate research articles.