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P.Johnson 1 Chapter 4 Experimental Research Designs.

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Presentation on theme: "P.Johnson 1 Chapter 4 Experimental Research Designs."— Presentation transcript:

1 P.Johnson 1 Chapter 4 Experimental Research Designs

2 P.Johnson 2 AIMS To outline deductive logic; To illustrate (laboratory) experimental research design; To give a management example of experimental design; To indicate why experimental logic is taken out of the laboratory; To illustrate quasi-experimental design.

3 P.Johnson 3 Deductive Logic Entails: 1.Reduction of theoretical statements to causal/predictive hypotheses that are testable. This entails: 2.Identification of: IndependentDependentVariable 3.NeutralizeExtraneous Effects of:Variables

4 P.Johnson 4 The Problems for Research Design in Deductive Research Methods for observing,Methods for observing manipulating andand measuring changes measuring the variationin the Dependent Variable of the Independent Variable (Problem D) (Problem E) IndependentDependentVariable (Problem A)(Problem B) Methods of controlling for, or ruling out, the influence of the Extraneous Variables (Problem F) Extraneous Variables (Problem C)

5 P.Johnson 5 Classical or True Experimental Research Design Two important requirements: 1.Control 2.Measurement Testing Hypotheses in Experimental Research Need to vary independent variable(s) and to investigate effects upon the dependent variable. In this need to have: 1.An experimental group 2.A control group

6 P.Johnson 6 Experimental Protocol and Procedure Application of Experimental Treatment by Experimenter PRE TREATMENTPOST TREATMENT Experimental Group E 1 Experimental Group E 2 matched Control Group C 1 Control Group C 2 no experimental treatment E 1 and E 2 Measure the incidence of the dependent variable, in the experimental group, prior to and after the experimental treatment. C 1 and C 2 Measure the incidence of the dependent variable, in the control group, prior to and after the occurrence of the experimental treatment in the experimental group. (Contd)

7 P.Johnson 7 Therefore E 2 - E 1 =De (the difference between the post and pre-treatment measures of the dependent variable in the experimental group). Similarly C 2 - C 1 = Dc(the difference between the post and pre-treatment measures of the dependent variable in the control group). If there is a difference between De and Dc it follows that this must have been caused by the experimental treatment.

8 P.Johnson 8 Two main methods for overcoming and controlling confounded extraneous variables in experiments: 1.The use of systematic controls 2.The use of randomization Both (1) and (2) are used so as to rule out, or control for, rival explanations, to the one being tested. (1) and (2) are physical controls as opposed to statistical controls.

9 P.Johnson 9 Hawthorne Studies - Western Electric Company, Chicago 1.Studies relationship between Physical workingand Employee conditions productivity therefore Independent Dependent Variable Lighting Output 2.Pre-treatment Post-treatment illumination variedExperimental Group E 1 Group E 2 Matched ProductivityProductivity Isolation MeasuredMeasuredControl Group C 1 Group C 2 No experimental treatments E 2 - E 1 = DeC 2 - C 1 = Dc Any difference between De and Dc must be due to the manipulation of the independent variable.

10 P.Johnson 10 Findings 1.Output in experimental group regardless of how illumination was varied. Simultaneously 2.Output in control group. These results and the results of similar experiments caused researchers to conclude that they were not simply looking at the effects of physical working conditions also Effects of employee norms and attitudes etc. Hawthorne effect or Experimental artefacts related to 1.Indexicality 2.Experimenter effects 3.Subjects mediation via interpretation.

11 P.Johnson 11 Why take research out of the laboratory? Five possible reasons: 1.Indexicality 2.Experimenter effects 3.Interpretation by subjects 4.Ethics 5.The nature of the research problem.

12 P.Johnson 12 Quasi Experiments Involve data from naturally occurring events. Therefore: 1.Researcher cannot manipulate independent variables 2.Control problematic Speeding Deaths on RoadsCrack-down Time The Connecticut Crack-down on Speeding

13 P.Johnson 13 An Example of a Quasi Experiment: Wall et al., 1986.

14 P.Johnson 14 From this research design - if the hypotheses regarding the impact of autonomous groups upon intrinsic and extrinsic job satisfaction, intrinsic job motivation, organizational commitment and mental health were to survive the test then: Employees in situations A1, A2, A3, B2 and B3 should record higher scores on these 5 variables than employees in situations B1, C1, C2 and D1 e.g. : B1< B2, B3 A1> B1, C1, D1 A2, B2 > C2 the results show that autonomous group working is a viable proposition...[which]...may have economic benefits. This is not as the theory predicts, because groups enhance operators motivation and effort; economic benefits stem instead from the logic of the groups themselves...indirect labour costs decrease and productivity benefits can accrue (Wall et al., 1986: 299-300).

15 P.Johnson 15 Conclusions: Deductive logic is expressed in a number of different research designs including laboratory experiments, quasi- experiments and (analytical) surveys/questionnaires; All attempt to test theory by deducing hypotheses and gathering data; All include in their design 1. manipulating/varying the causal or independent variable(s); 2. trying to control extraneous variables; 3. measuring variance in the dependent variable(s) - i.e. the effects. Different ways of doing 1-3 result in different deductive research designs.

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