Chapter 9: Experiments Flashcards
Experiment
A research approach in which one variable is manipulated and the effet on another variable is observed
Independent Variable
Variable the researcher manipulates directly such as price, packaging distribution, product features, etc
Dependent variable
Variables one doesn’t directly control such as sales or customer satisfaction
Treatment Variable
The independent variable manipulated during and experiment to measure its effect on dependent variables.
Extraneous Variables
Factors one does not control but has to live with such as weather.
Causal Research
Research designed to determine whether a change in one variable likely caused an observed change in another.
A causal relationship must demonstrate three things:
- Concomitant Variation (Correlation)
- Appropriate Time Order of Occurrence
- Elimination of Other Possible Causal Factors
Concomitant Variation
A statistical relationship between variables. If A causes B, then any change in A will also cause a change in B.
Appropriate Time Order of Occurance
Temporal Sequentiality. Change in an independent variable occurred before an observed change in the dependent variable.
If A causes B,then A must occur before B.
Elimination of Other Possible Causal Factors
“If you eliminate the impossible, whatever remains, however improbable, must be the truth.” - Sherlock Holmes
Hard to prove that something else did not cause change in B.
If A causes B, then there are no other letters.
Validity
Degree to which an experiment actually measures what it is trying to measure.
Internal Validity
The extent to which competing explanations for the experimental results observed can bar ruled-out.
External Validity
The extent to which causal relationships measured in an experiment can be generalized to outside persons, settings, and times.
Laboratory Experiment
Conducted in an controlled setting. Advantages: -Ability to control all variable - greater internal validity Disadvantages: - External validity - Not transferable to the actual marketplace
Maturation
Refers to changes in subjects throughout the course of the experiment that are a function of time and include such things as getting older, hungrier, tired, and the like.
Instrument variation
Refers to any changes in measurement instruments that might explain difference in the measurements taken. Ex. Two interviewers.
Selection Bias
Systematic differences betwee- whoops
Testing Effect
Result from the fact that the process of experimentation may produceits own effect on the responses we observe. Ex: ACT
Regression to the Mean
Refers to the observed tendency of subjects with extreme behavior to move toward the average for that behavior during the course of an experiment. People want to try to answer the “right answer.”
Experimental Deign
I an experimental design, the researcher has control over one or more independent variables, and manipulates one of more independent variables.
Non-experimental Design
Involve no manipulation and typically are referred to as “ex post facto” (after the fact) research.
“X”
Independent Variable
“O”
Dependent Variable
Experimental Treatment
Factors whose effects are to be measured and compared.
Control Group
The group in which the independent variable is not changed during the course of the experiment.
Test Group
The group that is exposed to manipulation (change) of the independent variable.
Experimental Effects
The effect of the treatment variable on the dependent variable.
An experimental design includes four factors
- The treatment of experimental variable must be manipulated
- The assignment of subjects to participate in the experiment
- A dependent variable to measure (Variable of Interest)
- Some plan or procedure for dealing with extraneous causal factors.
Field experiments
Tests conducted outside the laboratory Advantages: - Creates realism of the environment Disadvantages - Internal validity - No control over spurious factors
History
Refers to any variable or event other than those manipulated by the researcher that takes place between the beginning and end of the experiment and that might affect the value of the dependent variable.
Maturation
Refers to changes in subjects throughout the course of the experiment that are a function of time and include such things as getting older, hungrier, tired and the like.
Instrument Variation
Refers to any changes in measurement instruments that might explain differences in the measurements taken. (Two interviewers)
Selection Bias
Systematic differences between the test group and control group due to a biased selection process in making up the two groups. (Randomization and matching)
Mortality
Refers to the loss of test units or subjects during the course of an experiment. The problem is that those lost may be systematically different than those who stay.
Testing Effect
Testing effects result from the fact that the process of experimentation may produce its own effect on the responses we observe. Ex: GMAT and ACT tests
Regression to the Mean
Refers to the observed tendency of subjects with extreme behavior to move toward the average for that behavior during the course of an experiment.
Experimental Design
The research has control over one or more independent variables and manipulates one or more independent variables.
Non-Experimental Designs
Involve no manipulation and typically are referred to as ex post facto research.
“X”
Independent variable: indicates the exposure of an individual or a group to an experimental treatment.
“O”
Dependent Variable: Indicates a variable the researcher cannot change directly.
O1 X O2
Time Periods
X1 O1
X2 O2
For simultaneous exposure and measurement
Control Group
Independent variable isn’t changed
Test Grouop
Exposed to the manipulation of the treatment variable
Experimental Effects
The effect of the treatment variable on the dependent variable.
Four Factors of Experimental Design
- The treatment or experimental variable to be manipulated
- The assignment of subjects to participate in the experiment
- A dependent variable to measure
- Some plan or procedure for dealing with extraneous causal factors
Experimental Effects
The effect of the treatment variables on the dependent variable.
Randomization
The random assignment of subjects to treatment conditions to ensure equal representation of subject characteristics.
Physical Control
Holding constant the value or level of extraneous variables throughout the course of an experiment.
Design Control
Use of the experimental design to control extraneous causal factors
Statistical Control
Adjusting for the effects of extraneous variables by statistically adjusting the value for the dependent variable for each treatment condition.
Pre-Experimental Designs
Offer little or no control over extraneous factors
One-Shot Case Study
Pre-experimental design with no pretest observations, no control groups, and an after measurement only.
True Experimental Design
Research using an experimental group and a control group, to which test units are randomly assigned.
Quasi-experimental
Studies in which the researcher lacks complete control over the scheduling of treatments or must assign respondents to treatments in a nonrandom manner.
Interrupted Time-Series Designs
The treatment interrupts repeated measurements
Multiple Time-Series Designs
An interrupted time-series design with a control group.
Test Market
Real world testing of a new product or some element of the marketing mix using an experimental or quasi experimental design
