How long should an intervention be tried with little or no progress? Also, should two interventions be tried at the same time if both are beneficial and the student is progressing? Isn't the whole point progress?
Based on our research and others' research, we recommend 10-20 weeks of a validated tutoring program. We don't generally recommend two programs at the same time because (a) due to costs, reduces the number of students who can be tutored successfully and (b) it's possible that the two tutoring programs use different sequences/methods, which may be counterproductive.