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1、Chapter Eight,Chapter 8,Relationship of Experimentation to the Previous Chapters and the Marketing Research Process,Focus of This Chapter,Relationship toPrevious Chapters,Relationship to MarketingResearch Process,CausalityExperimentationExperimental Designs,Causal Research Design(Chapter 3),Problem
2、Definition,Approach to Problem,Field Work,Data Preparationand Analysis,Report Preparationand Presentation,Research Design,Figure 8.1 Relationship to the Previous Chapters and The Marketing Research Process,Experimentation as Conclusive Research,ConclusiveResearch,Descriptive,Causal,Experimentation,F
3、ield Experiments,LaboratoryExperiments,Figure 8.3 Experimentation as Conclusive Research,Concept of Causality,A statement such as X causes Y is called causality“X”is Cause and“Y”is effect Income Expenditure,Conditions for Causality,Concomitant variation is the extent to which a cause,X,and an effect
4、,Y,occur together or vary together in the way predicted by the hypothesis under consideration.The time order of occurrence condition states that the causing event must occur either before or simultaneously with the effect;it cannot occur afterwards.The absence of other possible causal factors means
5、that the factor or variable being investigated should be the only possible causal explanation.,Definitions and Concepts,Independent variables are variables or alternatives that are manipulated and whose effects are measured and compared,e.g.,price levels.Dependent variables are the variables which m
6、easure the effect of the independent variables on the test units,e.g.,sales,profits,and market shares.Extraneous variables are all variables other than the independent variables that affect the response of the test units,e.g.,store size,store location,and competitive effort.Test units are individual
7、s,organizations,or other entities whose response to the independent variables or treatments is being examined,e.g.,consumers or stores.,Experimental Design,An experimental design is a set of procedures specifying the test units and how these units are to be divided into homogeneous subsamples;what i
8、ndependent variables or treatments are to be manipulated;what dependent variables are to be measured;and how the extraneous variables are to be controlled.,Controlling Extraneous Variables,Randomization refers to the random assignment of test units to experimental groups by using random numbers.Trea
9、tment conditions are also randomly assigned to experimental groups.Matching involves comparing test units on a set of key background variables before assigning them to the treatment conditions.Statistical control involves measuring the extraneous variables and adjusting for their effects through sta
10、tistical analysis.Design control involves the use of experiments designed to control specific extraneous variables.,A Classification of Experimental Designs,Pre-experimental designs do not employ randomization procedures to control for extraneous factors.Examples are:the one-shot case study,the one-
11、group pretest-posttest design,and the static-group.In true experimental designs,the researcher can randomly assign test units to experimental groups and treatments to experimental groups.Examples are:the pretest-posttest control group design,the posttest-only control group design.,A Classification o
12、f Experimental Designs,Quasi-experimental designs result when the researcher is unable to achieve full manipulation of scheduling or allocation of treatments to test units but can still apply part of the apparatus of true experimentation.Examples are:time series and multiple time series designs.A st
13、atistical design is a series of basic experiments that allows for statistical control and analysis of external variables.Examples are:randomized block design,Latin square design,and factorial designs.,Figure 8.4 A Classification of Experimental Designs,Experimental Designs,StatisticalFactorial Desig
14、n,Quasi-Experimental Time SeriesMultiple Time Series,True ExperimentalPretest-Posttest Control Group Posttest-Only Control Group,Pre ExperimentalOne-Shot Case StudyOne Group Pretest-PosttestStatic Group,Figure 8.4 Classification of Experimental Designs,One-Shot Case Study,X01A single group of test u
15、nits is exposed to a treatment X.A single measurement on the dependent variable is taken(01).There is no random assignment of test units.The one-shot case study is more appropriate for exploratory than for conclusive research.,One-Group Pretest-Posttest Design,01 X02A group of test units is measured
16、 twice.There is no control group.The treatment effect is computed as 02 01.The validity of this conclusion is questionable since extraneous variables are largely uncontrolled.,Static Group Design,EG:X 01CG:02A two-group experimental design.The experimental group(EG)is exposed to the treatment,and th
17、e control group(CG)is not.Measurements on both groups are made only after the treatment.Test units are not assigned at random.The treatment effect would be measured as 01-02.,True Experimental Designs:Pretest-Posttest Control Group Design,EG:R01X02CG:R0304 Test units are randomly assigned to either
18、the experimental or the control group.A pretreatment measure is taken on each group.The treatment effect(TE)is measured as:(02-01)-(04-03).Selection bias is eliminated by randomization.The other extraneous effects are controlled as follows:02 01=TE+H+MA+MT+IT+I+SR+MO04 03=H+MA+MT+I+SR+MO=EV(Extraneo
19、us Variables)The experimental result is obtained by:(02-01)-(04-03)=TE+ITInteractive testing effect is not controlled.,Posttest-Only Control Group Design,EG:R X 01CG:R 02The treatment effect is obtained byTE=01-02Except for pre-measurement,the implementation of this design is very similar to that of
20、 the pretest-posttest control group design.,Quasi-Experimental Designs:Time Series Design,01 02 03 04 05 X 06 07 08 09 010There is no randomization of test units to treatments.The timing of treatment presentation,as well as which test units are exposed to the treatment,may not be within the research
21、ers control.,Statistical Designs,Statistical designs consist of a series of basic experiments that allow for statistical control and analysis of external variables and offer the following advantages:The effects of more than one independent variable can be measured.Specific extraneous variables can b
22、e statistically controlled.Economical designs can be formulated when each test unit is measured more than once.The most common statistical designs are the randomized block design,the Latin square design,and the factorial design.,Table 8.2 Laboratory Versus Field Experiments,Limitations of Experiment
23、ation,Experiments can be time consuming,particularly if the researcher is interested in measuring the long-term effects.Experiments are often expensive.The requirements of experimental group,control group,and multiple measurements significantly add to the cost of research.Experiments can be difficult to administer.It may be impossible to control for the effects of the extraneous variables,particularly in a field environment.Competitors may deliberately contaminate the results of a field experiment.,
