This study developed a summative scale that could be administered in a short time period to determine the Quality of Use (QOU) of an intervention used by teachers. The scale can be completed in less than an hour using easily attainable information. The QOU scale was applied to an elementary reading program to determine if the program results were dependent upon the quality of the fidelity of teacher use. The study focused on use of the Linguistic Pattern Series (LPS) portion of the Integrated Skills Method (ISM) Reading Program by 20 special education teachers in 13 elementary schools in San Antonio, Texas. Progress is measured by the use of the Decoding Skills Test (DST) (ISM Teaching Systems, Inc., 2004-b). To determine each teacher's QOU, a summative scale was developed composed of five items (Initial Placement, Frequency of Direct Instruction, Materials – LPS, Materials – Literature/Test Prep, and Scheduling) that possessed low-moderate cohesiveness of Alpha=.71. Results of the study showed a correlation between QOU summary scores and residualized DST Raw Score Grade Equivalent (RSGE) gains. The QOU could predict .771^2 = 50 percent of score variance. This is a strong prediction for a non-student external measure in education.