The theory behind GWA is that it is best to learn how to identify words by separating them into sound segments and recognizing those segments as specific patterns. Rather than teaching students to memorize letters, phonemes and rules, GWA practitioners present whole words as units of meaning. They also emphasize the process of learning to identify words toward the goal of applying decoding skills while reading in various contexts.
GWA is taught according to highly scripted steps. The method employs four levels of decoding sets, each containing a list of 30 word clusters of increasing difficulty. In one-on-one or small group sessions, an instructor presents and pronounces a word on a card, breaks it into phonograms, asks the student to identify and say these parts of the word several times and pronounces the word again. This intensive recognition and repetition process takes place in one or two 15 minute sessions per day.
According to "Teaching Children to be Literate: A Reflective Approach," an advantage of GWA is that nonprofessionals and parents can easily be trained how to use the system, because the exact steps and dialogue are spelled out in the official teacher guides. This allows for more opportunities for intensive practice and frees up teachers to spend time on whole classroom projects. Also, the GWA method may be used with other word lists and has proved to be successful in teaching adult learners, learning disabled students and those studying English as a second language.
While GWA has many champions, "Struggling Readers: Assessment and Instruction in Grades K-6" cites some concern with its "transferability to authentic reading contexts." If all of the allotted time for literacy learning is dedicated solely to word recognition practice, the publication contends, then students are being deprived of opportunities to use their skills in real-world reading and writing and may lag behind in comprehension. The publication also notes that the Glass decoding drills require intense focus and that the constant repetition can be tedious.