| Eras | Descriptions |
| From 1950s onward | · Era of behavioural science · Objective scientific model · Quantitative research methods · Survey & questionnaire were popular methods of data collection · Instrumental & descriptive perspectives |
| From 1980s onward | · Since mid-1986 onward researchers were more concerned with issues of ontology & epistemology · The era of globalization · Qualitative, naturalistic and subjective · Qualitative research methods · Arrival of conceptual perspective · Observation & interview were popular methods of data collection |
| From 2000 to 2016 | · Researchers beginning to use all of the conceptual, descriptive, humanistic, critical, evaluative, and instrumental perspectives to solve the issues in the field · Mostly evaluative perspective · Still survey and interviews but start of using other methodologies (case study, document analysis, video recording and more) |
| From 2016 to 2019 | · Viewing qualitative & quantitative as complementary and combing them (more mixed method research) · Greater interest in understanding social phenomenon of educational leadership in depth (more research toward ontology & epistemology) · Using more multiple case studies and mixed methods · Using a variety of data collection methods and analysis to interpret the experience of others and what they closely observe in a social context (interview, observation, focus group, document analysis, survey and questionnaire) · Use of all the perspectives in · Using more interpretive techniques to analysis the data |