Methods of research
Experimental research manipulates a variable to find cause and effect. Descriptive research describes what is. Historical research reconstructs the past. Qualitative and quantitative differ in words versus numbers.
Main methods
| Method | What it does | Typical tools | Example |
|---|---|---|---|
| Experimental | Manipulates the independent variable, controls others and measures the effect | Experimental and control groups, pre-test and post-test | Effect of flipped classes on marks |
| Descriptive (survey) | Describes present conditions as they are, without manipulation | Questionnaire, interview, observation, case study | Status of ICT use in colleges |
| Ex post facto (causal-comparative) | Looks back for likely causes of an effect that has already occurred | Comparison of existing groups | Why some districts have higher dropout |
| Historical | Reconstructs and interprets past events from records | Primary and secondary sources; external and internal criticism | Growth of women's colleges in a state |
| Qualitative | Explores meanings and experiences in natural settings | In-depth interview, focus group, participant observation | Lived experience of first-generation learners |
| Quantitative | Measures variables and tests hypotheses statistically | Structured tools, large samples, statistical tests | Relation of study hours to CGPA |
Historical research: two kinds of criticism
Primary sources are original records such as diaries, minutes and eyewitness accounts. Secondary sources are accounts written from them.
Quantitative vs qualitative
| Point | Quantitative | Qualitative |
|---|---|---|
| Data | Numbers | Words, images, observations |
| Logic | Mostly deductive; tests hypotheses | Mostly inductive; builds understanding or theory |
| Sample | Large, random | Small, purposive |
| Researcher | Detached | Close; the researcher is the main instrument |
| Designs | Experimental, survey, correlational | Ethnography, case study, phenomenology, grounded theory, narrative |
| Quality checks | Validity, reliability | Credibility, transferability, dependability, confirmability |
Words NET uses about experiments
- Independent variable (IV): the cause the researcher manipulates.
- Dependent variable (DV): the effect that is measured.
- Extraneous (confounding) variable: any other factor that may affect the DV; controlled by randomisation or matching.
- Internal validity: the change in the DV is truly due to the IV. External validity: results generalise beyond the study.
- Designs: pre-experimental (one-shot), quasi-experimental (no random assignment), true experimental (random assignment with a control group).
- Grounded theory (Glaser and Strauss) builds theory from data; phenomenology (Husserl) studies lived experience.
NET describes a study in two lines and asks which method it uses, tests IV/DV identification, and pairs qualitative designs with their key idea (grounded theory, ethnography, phenomenology).
Typical MCQ: “In a study of the effect of music on concentration, which is the independent variable?” Music, the factor manipulated. Concentration is the dependent variable that is measured.
Typical MCQ: “Checking whether an old manuscript is genuine is which type of criticism?” External criticism. Internal criticism checks whether its content is accurate and credible.
External = envelope (is the document genuine?), Internal = inside (is the content true?). The IV is what I vary; the DV depends on it.