Lesson Study. The researcher is the key instrument of data collection Creswell 2007.
This study was to describe the phenomenon on how English teachers experience their professional development through lesson study. To dig the deep
data and get a more holistic picture on how the particitpants experience the phenomenon, this study engaged in triangulation. The researcher collected the
data through observing the participants, interviewing the participants ‟ action and
activities, and giving questionnaire to some respondents. The multiple sources of data are to establish their trustworthiness or verification of the consistency of the
facts Creswell 2007. The questionnaire was to get the data on teacher‟s
professionalism from the students‟ point of view. The questionnaire was developed from the indicators stated in Table 2.1.
B. Nature and Sources of Data
The nature of data were 1 field notes, getting from observation on how the teachers act or do their activities which related to developing their professional
during they were doing the lesson study 2 narratives, getting from a sequence of in-depth interviews with two members of the lesson study, a supervisor and a
teacher who conducted a lesson in a school where she did not teach, and 3 written documents, getting from giving questionnaire to the students where the
lesson studies were conducted. The sources of the data were a lesson study group and two groups of
students. Considering to the ethical issues, all the names of the participants were kept in pseudonym. The lesson study group consisted of three Junior High School
English teachers who came from different schools in Sleman, a juniorhigh school
English teachers‟ supervisor in Sleman, and a teacher educator from a university. The two groups of students came from two different junior high schools in
Sleman. Both of the groups were students in grade seven and to whom the lesson study group conducted the lesson studies. All the members of the lesson study
group were as the participants andthe students were as the respondents of this study.
Considering the limited time, there were only two participants for the interview. I selected two persons of the group who I considered as rich sources.
Both of them have more than 20 years teaching experiences. One of them was the junior high school supervisor. She had more than a year experience as a junior
high school supervisor. The second interviewee had different experience compared with others. She was the teacher who implemented the lesson plan in a
school where she did not teach. Both of the interviewees experienced as the observers during the implementation of the lesson study in the live classrooms. I
interviewed them individually. I interviewed the supervisor after engaging in the first lesson study process. I thought there was only one cycle for the lesson study
but there were two cycles of the lesson study process. I interviewed her on April 25, 2012. The second interview was done to one of the teachers on May 8, 2012
after engaging in the second lesson study process. The interviews were delivered in Indonesian. The reason was that all participants were good in Indonesian. Using
Indonesian, they could narrate everything they had in their minds fluently and accurately. This happened because Indonesian had become their mother tongue.
Rich data from the participants were hoped to obtain. Although I believed that the participants were good in English, but it was not their second language. They used
it mostly in their teaching and special occasions. The use of Indonesian was also meant to build close relationship with the participants.
C. Instruments
