The purpose of this study was to analyze the effectiveness and the fidelity of reading or writing intervention programs. To meet the research purpose, the research questions were set up as follows: First, how did the selected studies consist their content elements of the program and how was each study’s fidelity turned out? Second, how were the selected studies’ effect sizes turned out? Third, is there any correlation between the program fidelities and effect sizes of the selected studies in relation to research design? The researcher selected 10 studies on reading or writing intervention from 2007 to 2012. Five studies employed experimental pre/post design and the other five did multiple baseline design. The results were as follows. First, the selected studies’ contents fidelities appeared from 63.8 to 83.3 percent point. Second, the effect sizes were turned out that the studies employing multiple baseline design showed higher effect size and fidelity than those of the studies by experimental pre/post design. Regrading these findings, the researcher discussed some aspects and each study’s result in terms of their fidelity and effect size in the discussion.