<p>Over the past two decades, evidence of mechanisms has achieved great relevance in methodology and philosophy of science. Several authors have argued that such evidence should play a more central role in scientific practice. Nonetheless, important concerns have been raised regarding the variable quality of evidence of mechanisms and the reliability of mechanism-based reasoning. In this paper, in response to those concerns, I address the assessment and evaluation of evidence of mechanisms. I first analyse and discuss previous contributions on the topic. Although valuable, these proposals face a number of significant limitations. Building on them, I then introduce and develop the Support-Absence Framework. This framework integrates support and absence-of-error criteria to assess evidence of mechanisms. To explore and illustrate the application of this framework, I consider process tracing and agent-based modelling.</p>