2000...2...2...2...3...3...4...6...6...6...6...7...7...7...8...8 RANDOMIZATION...8 CONTROL VARIABLE...9 TRUE EXPERIMENTAL DESIGN...9 PRETEST-POSTTEST CONTROL GROUP DESIGN..9 POST-ONLY CONTROL DESIGN...10 THE SOLOMON FOUR-GROUP DESIGN...11...12 EXTERNAL AND INTERNAL VALIDITY...12 EXTERNAL VALIDITY...12 INTERNAL VALIDITY...14...15...17 STRENGTHS...18 WEAKNESSES...18 1
...20 2
3
4
5
Karl Popper, 1968 6
1. 2. 3. 4. 5. 7
TIME 1 TIME 2 TIME 3 randomization 1. random sampling 2. random assignment 8
control variable MAX-MIN-CON 1. maximize experimental variance 2. minimize error variance 3. control extraneous variance True experimental design pretest-posttest control group design pretest-posttest equivalent-group design 1. 2. 9
post-only control design posttest-only, equivalent-group design 1. 2. 3. 4. 10
t The Solomon four-group design R.L. Solomon 2 2 11
84 External and Internal Validity validity generalizability causal relationships between independent variables and dependent variables External Validity 12
2000:276 natural life situations 1929 Hawthorne Effect Williamson1982:223 Threats to External Validity WilliamsonKarpDalphinGray1982:223-224 1. Modelling Effect Expectancy of Modelling Effect 2. Sampling and Generalizability representativeness Williamson1982:225 13
Internal Validity 2000:275-276 Mill 1 2 3 Blum & Foos1986:113 Threats to internal validity Blum Foos1986113-116 Williamson et al.1982:220-221 Singleton et al.1988:202-204 Kidder Judd 1986:75-78 1. History 2. Maturation 3. Testing 4. Regression 14
5. Instrumentation or Instrumental Change 6. Attrition or Experimental Mortality random assignment neutralized Special Problems about Experimental Design Singleton et al.1988:185 Blum Foos1986:126-128Singleton et al. 1988:186-190Blalock1970Hardyck Petrinovich1975 15
1. Demand Characteristics Demand Characteristics cues Orne Evans1965 demand Singleton et al. 1988:186-187 2. Evaluation Apprehension Evaluation Apprehension 3. Other Motives of Experimental Subjects Argyris1968 Singleton et al.1988:188 4. Experimenter Effects 16
Robert Rosenthal 1966 Singleton etc.1988:189 expectations 5. 6. feedback 1968 17
Strengths 1 causal relationships 2 descriptive studies 3 4 5 Weaknesses 1 nonlinear model 2 nonexperimental design 3 4 5 maternal care personality 6 18
7 8 19
2000 1968 1999 Blalock, H. M.1970 1983 An introduction to social research Blum, Milton L, Foos, Paul W.1986Data gathering: Experimental methods plus. New York: Harper Row. Borg, Walter R. Gall, Meredith D.1989Educational research5 th ed.. New York: Longman. Brown, Steven R. Melamed, Lawrence E.1990Experimental design and analysis. London: Sage. Hardyck, Cutris, Petrinovich, Lewis F.1975Understanding research in the social sciences. Philadelphia: W. B. Saunders. Kidder, Louise H., Judd, Charles M.1986Research methods in social relations 5 th ed.. New York: CBS College Publishing. Phillips, Bernard S.1976Social research3 rd ed.. New York: Macmillan. Riecken, Henry W.1974Social Experimentation. New York: Academic Press Inc. Shipman, Marten1997The limitation of social research4 th ed.. New York: Addison Wesley Longman Limited. Sanders, William B., Pinhey, Thomas K.1983The conduct of social research. New York: CBS College Publishing. Singleton, Royce Jr., Stratis, Bruce C., Straits, Margaret M., McAllister, Ronald J. 1988Approaches to social research. Oxford: Oxford University Press. Williamson, John B., Karp, David A., Dalphin, John R., Gray, Paul S.1982The research craft: An introduction to social research methods2 nd ed.. Boston: Scott, Foresman. 20