CH11 Experimentation & Test Markets Flashcards
(33 cards)
define an experiment
experiment: a research approach in which one variable is manipulated and the effect on another variable is observed
what is the purpose of experimental research?
experimental research is used to test whether a change in an independent variable causes a predictable change in a dependent variable
what is causal research?
causal research: research designed to determine whether a change in one variable likely caused an observed change in another
what are the 3 criteria to establish causality in experimental research?
- correlation or concomitant variation
- appropriate time order of occurrence
- elimination of other possible causal factors
what are the 2 types of experimental settings?
- laboratory experiments
- field experiments
what is the difference between laboratory experiments and field experiments?
laboratory experiments are conducted in controlled settings, while field experiments take place in the actual marketplace
what are internal and external validities in experimentation?
internal validity refers to ruling out competing explanations of experimental results, while external validity relates to generalizing the findings to other settings
what are extraneous variables in experimental research?
extraneous variables: other independent variables that may affect the dependent variable and hinder the ability to conclude a causal relationship between the treatment variable and the dependent variable
list some examples of extraneous variables
- history: intervention, between the beginning and end of an experiment, of outside variables or events that might change the dependent variable
- maturation: changes in subjects occurring during the experiment that are not related to the experiment but that may affect subjects’ response to the treatment factor
- instrument variation: changes in measurement instruments (eg. interviewers or observers) that might affect measurements
- selection bias: systematic differences between the test group and the control group due to a biased selection process
- mortality: loss of test units or subjects during the course of an experiment, which may result in a nonrepresentativeness
- testing effect: the effect that is a by-product of the research process itself
- regression to the mean: the tendency of subjects with extreme behaviour to move toward the average for that behaviour during the course of an experiment
what are the 4 basic approaches used to control extraneous factors in experiments?
- 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 cofounded variables by statistically adjusting the value of the dependent variable for each treatment condition
define experimental design
experimental design: the test in which the researcher has control over and manipulates one or more independent variables
what are the 4 elements of an experimental design?
- a treatment variable
- subjects
- a measured dependent variable
- a plan for dealing with extraneous causal factors
what are some limitations of experimental research?
- high cost
- security issues
- implementation problems
what are the characteristics of pre-experimental designs?
pre-experimental designs offer limited control over extraneous factors and include designs such as the one-shot case study and the one-group pretest-posttest design
provide an example of a pre-experimental design
an example of a pre-experimental design is the one-shot case study design, which involves exposing test units to a treatment variable and measuring the dependent variable afterward, without a control group or pretest observations
describe the one-shot case study design
the one-shot case study design is a pre-experimental design where test units are exposed to a treatment variable, and the dependent variable is measured afterward, without a control group or pretest observations
what are the weaknesses of the one-shot case study design?
its weaknesses include the absence of pretest observations and a control group, making it difficult to establish causal inferences and lacking internal and external validity
what is the one-group pretest-posttest design?
the one-group pretest-posttest design is a pre-experimental design where a single group of subjects or test units is measured before and after receiving the treatment, without a control group
what are the strengths and weaknesses of the one-group pretest-posttest design
its strengths include simplicity and cost-effectiveness
however, it is vulnerable to threats like history and maturation, and without a control group, it cannot estimate the true impact of the treatment
what are true experimental designs and how do they differ from pre-experimental designs?
true experimental designs involve the random assignment of test units to experimental and control groups, providing better control over extraneous factors and enabling causal inferences
they differ from pre-experimental designs by incorporating essential elements such as randomization, control groups, and pretest observations
explain the before and after with control groups. how is the treatment effect estimated in this design?
the before and after with control group design is a true experimental design where test units are randomly assigned to experimental and control groups. pretest and posttest measurements are taken for both groups.
the treatment effect is estimated by comparing the difference between the pre- and postmeasurements of the experimental group with the difference in the control group, removing the influence of extraneous factors.
what are the major threats to validity in the before and after with control group design?
the major threats to validity in the before and after with control group design are mortality (when units drop out and differ systematically) and history (when events outside the experiment influence the experimental group differently)
these threats can affect the internal validity of the design
describe the after-only with control group design. what are its limitations?
the after-only with control group design is a true experimental design where test units are randomly assigned to experimental and control groups, but only postmeasurements are taken
its limitations include the lack of premeasurements, making it difficult to establish the baseline and estimate the true treatment effect accurately
what are quasi-experiments, and why are they used in marketing research?
quasi-experiments are studies in which the researcher lacks complete control over treatment scheduling or must assign respondents to treatments in a nonrandom manner
they are used in marketing research due to cost and field constraints that make it challenging to exert direct control or randomization. quasi-experiments provide more feasible options in field settings