RtI thinking tells me that if 80% of my students are achieving proficiency, then what I am already doing is working for most learners.  RtI is a framework for refining practice and process to better reach the other 20% of learners. 

Try something new consistently for set amount of time.  Measure to see if the learner is making gains.  Reflect on the resluts.  Make a plan to continue the intervention, try another intervention, or return to core programming.

When I apply the RtI process, I am making a genuine, scientific attempt to ensure learning for all students.

Our job is to keep working at teaching until learning occurs.  Sure, RtI has its critics.  But are they offering any better ideas?