What is the Best Evidence to Support Your Claims?

In academic/scientific writing, your claims need to be supported by the best quality evidence.
You cannot write that ‘smoking causes cancer’ without a piece of factual, credible evidence supporting your claim.

The type of evidence you use will either reinforce your claims or leave your tutor suspicious about the validity of your claims and your writing authority.

Therefore, it’s crucial that you use convincing evidence to support your arguments.

That raises the question of what actually constitutes the best evidence.
Research evidence differs tremendously in quality and bias.

Yet, certain research designs seem to have more strengths than others.
The Evidence-Based Pyramid will help you understand that there are different levels of evidence.
The lower levels of the pyramid show studies which are usually more biased and less rigorous.
The higher levels represent research using stronger designs e.g. experimental studies (RCTs).

If you want to provide good evidence supporting the claim that smoking causes cancer, you should consider using meta-analyses, systematic reviews or randomized controlled trials.  These types of evidence are usually more rigorous and reliable than e.g. surveys or case studies.

This paper looks like a good candidate for strong evidence

Just a word of warning

The pyramid should not be used to judge the value of the study you are about to use to support your statements. There are many low-quality, questionable meta-analyses, and biased randomized-control studies. Great-quality, considerate case studies, well-done surveys, and qualitative evidence should not be dismissed as a source of scientific evidence. The Evidence-Based Pyramid is more a rule of thumb – a principle which application is not intended to be always accurate or reliable.