Based on the research finding which has been discussed, the researcher makes the conclusion as follow:
1. Reading comprehension ability of the students in experimental group belonged to excellent category, because the mean score of experimental group post-test was 80.55.
2. The T-test value is higher than the T-table (4.98>2.000). In addition, the mean score of experimental group before the researcher gave the treatment by using TAI method is 71.07, and the mean score after the researcher gave the treatments by TAI method is 80.55. It means that the mean score improved than before. From the T-test value, it can be concluded that the alternative hypothesis states that using Team Assisted Individualization (TAI) method is effective to improve reading comprehension ability in narrative text for eighth grade students of SMP N 25 Purworejo in the academic year 2012/2013 is accepted.