If you think back to this past summer, when you joined your fellow freshmen team teachers, you might remember an image similar to this. After the reauthorization of IDEA in 2004, schools were provided with an alternative to the discrepancy model (the model used to identify students with special learning needs by checking if the student exhibits between one to two years performance behind what the student's IQ says should be the level of performance). With this new system, schools were no longer required to wait for a student to fail, but instead, could use scientifically validated interventions to monitor a student's reaction to varied instruction.
The first step in this process is what is called Universal Interventions, or Tier 1. By using research-based strategies that have a high probability of yielding success, teachers work to try to serve at least 80% of students within the classroom, before pulling them out or scheduling them for supplemental interventions (Tier 2).
This is basically the "just good teaching" that all students should receive everyday--research-baed curriculum, effective teaching strategies, and continuous assessment.