Definition of Experimental Research

1. J. Strebel Definition of Experimental Research In an experiment, the researcher changes one element, the explanatory or independent variable (IV), to observe the effect of that change on another element, the dependent variable (DV).

2. J. Strebel What is an Experiment?

3. J. Strebel Explanation of Causation Typically in an experiment, the researcher wants to assert that the change in the IV causes the change in the DV. To prove causation, the researcher must demonstrate three things: Concomitant variation Appropriate time order Elimination of other possible causal factors

4. J. Strebel Explanation of Causation Concomitant variation - the IV and the DV must vary together in some predicable fashion For example, a positive relationship, such as an increase in disposable income together with an increase in sales of luxury cars Also possible, an inverse relationship, such as an increase in disposable income together with a decrease in sales of low quality hamburger

5. J. Strebel Explanation of Causation Appropriate time order - the change in the IV must precede the change in the DV A cannot cause B if A does not occur before B does

6. J. Strebel Explanation of Causation Elimination of Other Possible Causal Factors �Nonspuriousness� - the researcher should be able to eliminate any other potential explanations to account for the change in the DV Example: Music at work?

7. J. Strebel Explanation of Causation A study is considered confounded if there is more than one IV that could have caused the effect. Confounded variables provide skeptics with easy counter-explanations for the results In the subliminal tape example, the exposure of employees to subliminal messages is perfectly confounded with the introduction of music at the workplace

8. J. Strebel Evidence of Causation

9. J. Strebel Explanation of Causation Another way of stating �nonspuriousness� is to say that extraneous causal factors must be eliminated. We want to show that our explanation of the phenomena is the best and that there aren�t other factors involved. This is the most difficult thing to demonstrate.

10. J. Strebel Explanation of Causation Extraneous variables therefore need to be �designed out� of our experiments. Some examples of extraneous variables: History Takes place between beginning and end of experiment but is not controlled by experimenter Maturation Changes in subjects that are a function of time (getting tired, hungry, older, etc.)

11. J. Strebel Explanation of Causation Extraneous variables continued: Instrument variation Changes in the administration of the test measures (example: interviewer bias) Selection bias The experimental group is significantly different from the population of interest or control group Mortality Respondents drop out during the course of the experiment

12. J. Strebel Explanation of Causation Extraneous variables continued: Testing effect The process of experimentation produces its own effects on the observed responses Also called demand effect Regression to the mean There is an observed tendency of subjects with extreme behavior to move toward the average for that behavior during the course of the experiment

13. J. Strebel Basic Experimental Issues Experimental design and treatment In an experimental design the researcher has control over and manipulates one or more independent variables Four factors: The IV, also known as treatment (manipulated) The subjects, both experimental and control The DV (what is being measured) The plan or procedure to deal with extraneous variables

14. J. Strebel Basic Experimental Issues Experimental Effects The term experimental effect refers to the effect of the treatment (independent) variable(s) on the dependent variables. The goal is to determine the effect of each treatment condition (level) on the dependent variable.

15. J. Strebel The Effect of Gender on Gays� and Lesbians� Attitude Toward Advertising Content: The Role of Subcultural Code IV: Varying degrees of gay advertising content Mainstream, coded, male-oriented, lesbian-oriented DV: Attitude towards the ad The ad is: Very bad : : : : Very good What is your opinion of the ad? Very unfavorable : : : : Very favorable Please rate how you felt about the ad Liked very much : : : : disliked very much H1: Gays and lesbians will have a more positive attitude towards ads with homosexual imagery than ads with mainstream imagery.

16. J. Strebel The Effect of Gender on Gays� and Lesbians� Attitude Toward Advertising Content: The Role of Subcultural Code Method: Pilot test: 54 consumers Participants were presented with four ads (4 degrees of gay advertising content) Reviewed ad, answered three-item attitude towards ad measure Results: Results indicate an overall difference for attitude toward the ads Possible Problems: Did not control for product category or brand type Manipulation check: measure the perceived gayness of the ad content Presentation randomized to control for order effects Demographics

17. J. Strebel Limitations to Experiments Why aren�t experiments used more often? High cost Security issues Implementation problems

18. J. Strebel Experimental Validity Validity is measuring what you intended to measure. To do so, you must reduce systematic and random error. There are two types of experimental validity: Internal validity External validity

19. J. Strebel Experimental Validity Internal validity refers to the extent to which competing explanations for the experimental results observed can be avoided. Avoid confounds

20. J. Strebel Internal Validity

21. J. Strebel Basic Experimental Issues There are four basic approaches to controlling extraneous causal factors: Randomization in assigning subjects to treatment conditions Physical control of the extraneous factor - holding it constant Design control of extraneous factors through the specific type of experimental design used Statistical control through identifying and measuring the effects of the extraneous factors throughout the experiment

22. J. Strebel Experimental Validity External validity refers to whether the causal relationships measured in an experiment can be generalized to outside persons, settings, and times. A common example (in medicine not marketing) is: Can studies on cancer in rats be extended to human cancers?

23. J. Strebel External Validity

24. J. Strebel External Validity

25. J. Strebel Experimental Settings The debate: Laboratory experiments vs. field experiments. In a laboratory experiment, the experimenter can control more variables which helps prove causality In a field experiment (i.e., the test is conducted in a real world setting), the study is more realistic in terms of the marketplace

26. J. Strebel Internal and External Validity

27. J. Strebel Test Markets Test marketing refers to the testing of a new product or any change in the marketing strategy in the field. Use a single market, group of markets or a region of the country Involve the use of experimental procedures

28. J. Strebel Test Markets Test market usage and objectives Used to evaluate proposed national programs by: Estimating market share and volume Estimating effect on other items that the company markets (cannibalization rate) Collecting data about potential customers Analyzing reactions and behavior of competitors

29. J. Strebel Test Markets Cost of test marketing Direct costs Marketing mix costs (ads, P-O-P, coupons, etc.) Outside vendors (marketing research, ad agencies) Higher trade allowances to obtain distribution Indirect costs Management time, diversion of attention Negative impact on trade, reputation if fails Negative impact of competitors gaining info.

30. J. Strebel Test Markets Should we or shouldn�t we? Compare the costs and benefits... Costs discussed above Benefits include: Good method for estimating product sales potential under realistic market conditions Opportunity to identify and correct weaknesses in the marketing mix

31. J. Strebel Test Markets Four factors to consider Tradeoff costs and risks of product failure with potential profits and probability of success How quickly can competitors respond or copy the product? Consider the investment required to produce the product for the test market Appraise impact of a product failure on the company�s reputation

32. J. Strebel Test Markets Three types of test market approaches Standard test markets

33. J. Strebel Test Markets Simulated test markets Laboratory approach Mall intercept to obtain subjects Exposure to product prototype and advertisements Given opportunity to buy the new product Could also be given product to use and contacted later for an assessment Mathematical models used to create predictions Trial and repeat purchase estimates

34. J. Strebel Test Markets How to select a market for the test: Not an overtested market Sales of that type of product should be typical Avoid unusual demographics Consider regional differences Little media spillover Moderately sized markets Generalizable distribution channels and competitive situation Differing cities should have similar demographics

35. J. Strebel Test Markets Analysis of test market results Purchase data Trial Repeat rate - % of initial triers who made second+ purchases Awareness data Competitive response Source of sales (cannibalization?)