Eight books were chosen to answer the given research questions and analytical problem at hand using relevant sampling or also called purposive sampling (Riffe, Lacy & Fico, 1998 cited in Krippendoff,2004). The relevant samples were selected from past decade 2003-2011 to solve ELT problems with known expertise as the sources of data for solving ELT problems.
The documents included the curriculum for studying English in Thai primary and secondary schools and relevant books or papers obtained from the Office of Basic Education Commission in the Ministry of Education.
The resources chosen were categorized as follow: