Meadows quant res dese


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Meadows quant res dese

  1. 1. Quantitative Research Design Ken N. Meadows, Ph.D. Educational Researcher Teaching and Learning Services
  2. 2. Outline Defining quantitative research design Non-Experimental designs  Descriptive  Correlational Experimental designs  Experiments  Quasi-experiments Conclusions… 2
  3. 3. Definitions Research design: the framework used to conduct the research Research method: data collection techniques (e.g., document analysis, interview, survey) 3
  4. 4. Definitions Quantitative research2,6: Assumptions:  Reality - objective & singular  Researcher - independent from research  Research - value-free, unbiased  Research process – deductive (generate hypotheses from theory), emphasize cause/effect, isolation of variables, context-free, prediction, generalizability 4
  5. 5. Definitions Quantitative research2,6: Methods: larger scale (e.g., survey) Data: quantitative (numbers) Analysis: statistical 5
  6. 6. Definitions Qualitative research2,6: Assumptions:  Reality – subjective & multiple (from participants’ perspective)  Researcher – interacts with research  Research – value-laden, biased  Research process – inductive (generate theory from data), emergent variables (identified during research), patterns identified 6
  7. 7. Definitions Qualitative research2,6: Methods: smaller scale (e.g., interviews) Data: qualitative (words) Analysis: thematic 7
  8. 8. Definitions Two broad categories of quantitative designs:  Non-experimental  Experimental A major difference - validity of the designs7  Internal validity: extent design can identify causal relationships & rule out alternate explanations of relationships between variables  External validity: extent design allows conclusions to generalize beyond the confines of study 8
  9. 9. Definitions  Non-experimental designs tend to be low in internal validity but higher in external validity  Experimental designs tend to be high in internal validity but lower in external validity 9
  10. 10. Non-experimental Non-experimental designs:  Descriptive  Correlational Descriptive designs5,7 - identify the characteristics of a phenomenon Describe the variable under investigation – not examine relationships among variables For example: LARSN needs assessment (Hoffman, Meadows, & Martin-Gardiner, 2009) 10
  11. 11. Non-experimental Correlational designs examine relationships among variables under investigation1,5,7 Tend to examine relationships as they exist Do not isolate & manipulate variables to establish causal relationships as in experimental research 11
  12. 12. Non-experimental For example, Eron, Huesmann, Lefkowitz, & Walder (1972) examined relationship between preferences for violent television & aggressive behaviour 12
  13. 13. Non-experimental Cannot make causal statements with correlational research1,5,7  Directionality problem (if X <-> Y, does X ->Y or Y ->X)  Third variable problem (if X <-> Y, possible X<-Z->Y) 13
  14. 14. Non-experimental More complex correlational designs can suggest direction of causality E.g., Cross-lagged panel correlation design Eron and colleagues (1972) – collected data at grade 3 &13 and correlated variables between years – found moderate correlation between grade 3 preference for violent tv & grade 13 aggressive behaviour 14
  15. 15. Non-experimental In groups of 3, please discuss:  Research question you would be interested in researching  Design of your research (i.e., descriptive or correlational)   Data sources for that project  Research methods you would use 15
  16. 16. Experimental Experimental designs:  Experimental  Quasi-experimental Experiment1,3,5,7 - variable is systematically manipulated (independent variable; IV) to observe effect of manipulation on another variable (dependent variable; DV) 16
  17. 17. Experimental Experimental control1,3,5,7 – hold extraneous variables constant in experiment to isolate effect of IV on DV For example, Hopkins & Wilson (2009) 17
  18. 18. Experimental Common experimental design: pre-test/post-test control group design1,3,5,7 Measure Exposure Measure Before AfterTreatment 01 X 02GroupControl Group 03 04 18
  19. 19. Experimental If change from pre- to post-test for treatment group & not control group (or not as much), change can be attributed to the treatment (assuming proper experimental controls) Controlling for extraneous variables1,3,5,7:  Participant differences: random assignment of participants to treatment and control groups or matching  Situational differences: hold situations constant 19
  20. 20. Experimental Pre-test/Post-test Control Group7 – possible pre- test influences treatment (threat to external validity) Post-test only control design7: Exposure Measure After Treatment X 01 Group Control Group 02 20
  21. 21. Experimental Post-test only control group – groups should be same on DV before treatment because of random assignment Other threats to external validity for experiments8:  Interaction effect of selection bias and treatment  Reactive effects of the experiment 21
  22. 22. Experimental Quasi-experimental designs5,8: not true experiments because the groups tend to be naturally occurring not groups created by researcher Try to match participants and control for situational variables as much as possible 22
  23. 23. Experimental Common quasi-experimental design: pre-test/post- test non-equivalent group design8 Measure Exposure Measure Before AfterTreatment 01 X 02GroupControl Group 03 04 23
  24. 24. Experimental Example: Haffie, Meadows, Dunn, & Graves (2009) quasi-experimental research higher in external validity than experiments (reflect real life more) but weaker in internal validity than experiments (do not control for all extraneous variables) 8 24
  25. 25. Experimental In groups of 3, please discuss:  New research question you would be interested in researching  Design of your research (i.e., experimental or quasi- experimental)   Data sources for that project  Research methods you would use 25
  26. 26. Questions, comments… 26
  27. 27. References1. Bordens, K. S. & Abbott, B. B. (2008). Research design and methods: A process approach (7th ed.). Boston: McGraw-Hill.2. Creswell, J. W. (1994). Research design: Qualitative and quantitative approaches. Thousand Oaks, CA: Sage Publications.3. Elmes, D. G., Kantowitz, B. H., Roediger III, H. L. (1999). Research methods in psychology (6th ed.). Pacific Grove, CA: Brooks/Cole Publishing Company.4. Eron, L. D., Huesmann, L. R., Lefkowitz, M. M. & Walder, L. O. (1972). Does television violence cause aggression? American Psychologist, 27, 253-263. 27
  28. 28. References5. Leedy, P. D., & Ormrod, J. E. (2001). Practical research: Planning and design (7th ed.). Upper Saddle River, N.J.: Merrill Prentice Hall.6. OLeary, Z. (2004). The essential guide to doing research. London: Sage.7. Powell, R. R., & Connaway, L. S. (2004). Basic research methods for librarians (4th ed.). Westport, Conn.: Libraries Unlimited. 28