The aim of this research was to find out whether or not there was any
effect of PWIM in teaching writing of descriptive text. This research was
conducted in SMP Muhammadiyah 1 Purwokerto in academic year 2017/2018.
This research used quasi experimental research. There were two groups of which
class VIIE was used as a control group and VIIF was used as the experimental
group. This research used purposive sampling to determine the sample. Test was
used in collecting data of this research, namely pre-test and post-test. The test was
distributed to both groups. After that, the data was analyzed using t-test to know
the effectiveness of PWIM. Based on the computation, t-test result was 2.11 and
the result of t-table at the significan
ce level 0.05 with degree of freedom 36 was
1.68, so the calculation of t-test was higher than t-table (2.11>1.68). It could be
c
oncluded that PWIM was effective for teaching writing of descriptive text at
seventh grade students of SMP Muhammadiyah 1 Purwokerto in academic year
2017/2018.