The medical research literature contains plenty of contradictory results (and has a strong publication bias). Attempting to make more informed decisions, I would like to educate myself to judge how much importance I should give to the results presented in a given medical research article. For the sake of concreteness, let's assume we only consider medical research articles that study the impact of drug X or medical treatment Z on medical condition Z.
What are the criteria for assessing the quality of evidence in such medical research articles?
For example, Atkins, David, Dana Best, Peter A. Briss, Martin Eccles, Yngve Falck-Ytter, Signe Flottorp, Gordon H. Guyatt et al. "Grading quality of evidence and strength of recommendations." BMJ (Clinical research ed.) (2004). Harvard proposed the following:
which they applied to a few research articles to exemplify the use of their assessment grid:
I wonder whether there exist other similar attempts to lay out a systematic, objectively applicable assessment strategy.
I am aware of the Level of Evidence pyramid (image from the MOOC Introduction to Systematic Review and Meta-Analysis https://www.coursera.org/learn/systematic-review):
Note that I am only interested in assessing the quality of the evidence, and not the quantity of the entire research article. For instance, the quality of writing or the quality of the literature review could be an element to the judge the quality of the research article, but is not useful when the judging the presented evidence.