1 Introduction 1.1 What is a mechanism? 1.2 Where does evidence of a mechanism come from? 1.3 Why consider evidence of mechanisms? 1.3.1 Evaluating efficacy 1.3.2 Evaluating external validity 1.3.3 Other questions 1.3.4 Importance of considering evidence of mechanisms 2 How to consider evidence of mechanisms: a summary 2.1 Questions to address 2.2 Quality level of evidence and status of claim 2.3 Identifying evidence of mechanisms in the literature 2.4 Evaluating evidence of mechanisms 2.5 Using evidence of mechanisms to evaluate causal claims 2.6 Overall approach 3 Identifying evidence of mechanisms in the literature 3.1 Hypothesize a mechanism 3.2 Search the literature 3.3 Identify the evidence most relevant to the mechanism hypothesis 3.4 Presenting the evidence of mechanisms 4 Evaluating evidence of mechanisms 4.1 Considerations for evaluating evidence of mechanism 4.2 Presenting quality of evidence of mechanisms 5 Using evidence of mechanisms to evaluate efficacy and external validity 5.1 Efficacy 5.2 External validity 6 Glossary 7 References 8 Acknowledgements 9 Appendix A. A critical appraisal tool for evidence of mechanisms 10 Appendix B. GRADE tables with mechanism assessment 11 Appendix C: Databases for evidence of mechanisms 12 Appendix D: Assessing exposures 12.1 Example: carcinogenicity of benzo[a]pyrene 12.2 Comparison to IARC 12.3 Molecular epidemiology 12.4 Comparison to SYRINA ukryj opis