Experimental Research

EXPERIMENTEXPERIMENT

A RESEARCH INVESTIGATION IN WHICH CONDITIONS ARE CONTROLLED

ONE INDEPENDENT VARIABLE IS MANIPULATED (SOMETIMES MORE THAN ONE)

ITS EFFECT ON A DEPENDENT VARIABLE IS MEASURED

TO TEST A HYPOTHESIS

Manipulation of the Independent Variable

Selection of Dependent Variable

Assignment of Subjects (or other Test Units)

Control Over Extraneous Variables

Basic Issues of Experimental DesignBasic Issues of Experimental Design

•Classificatory Vs. Continuous Variables

•Experimental and Control Groups

•Treatment Levels

•More Than One Independent Variable

Manipulation of Independent VariablesManipulation of Independent Variables

Experimental treatments are the alternative manipulations of the independent variable being investigated.

DEPENDENT VARIABLEDEPENDENT VARIABLE

Its value is expected to be dependent on the experimenter’s manipulation

Criterion or standard by which the results are judged

• Selection- e.g., sales volume, awareness, recall

• Measurement

Dependent VariableDependent Variable

TEST UNITS - subjects or TEST UNITS - subjects or entities whose response to the entities whose response to the experimental treatment are experimental treatment are measured or observed.measured or observed.

•Constant Error

•Random Errors

Two Types of Experimental ErrorTwo Types of Experimental Error

•Elimination of Extraneous Variables

•Constancy of Conditions

•Order of Presentation

•Blinding

•Random Assignment

Controlling Extraneous VariablesControlling Extraneous Variables

DEMAND DEMAND CHARACTERISTICSCHARACTERISTICS

EXPERIMENTAL PROCEDURES THAT INTENTIONALLY HINT TO SUBJECTS SOMETHING ABOUT THE EXPERIMENTER’S HYPOTHESIS

• Guinea Pigs

• Hawthorne Effect

Demand CharacteristicsDemand Characteristics

Field vs. Laboratory ExperimentField vs. Laboratory Experiment

Laboratory Experiment Field Experiment

Artificial-Low Realism

Few ExtraneousVariables

High control

Low Cost

Short Duration

Subjects Aware ofParticipation

Natural-High Realism

Many ExtraneousVariables

Low control

High Cost

Long Duration

Subjects Unaware ofParticipation

WHEN IS AN EXPERIMENT WHEN IS AN EXPERIMENT INTERNAL VALIDITY?INTERNAL VALIDITY?

INTERNAL VALIDITY – Confidence that the only cause of change in the dependent variable came because of a change in the independent variable.

Did the manipulation do what it was supposed to do?

• History

• Maturation

• Testing

• Instrumentation

• Selection

• Mortality

Factors Influencing Internal ValidityFactors Influencing Internal Validity

Type of Extraneous VariableType of Extraneous Variable ExampleExample

History - specific events in theEnvironment between the Beforeand After Measurement That Are beyond the Experimenter’s Control

Maturation - subjects Changeduring the Course of the Experiment

Testing - The Before Measure Alertsor Sensitizes Subject to Nature of Experiment or Second Measure.

A Major EmployerCloses Its Plant inTest Market Area

Subjects Become Tired

Questionnaireabout the TraditionalRole of Women Triggers Enhanced Awareness of Womenin an Experiment.

Other FactorsOther Factors ExampleExample

Instrument - Changes inInstrument Result in Response Bias

Selection - Sample SelectionError Because of DifferentialSelection Comparison Groups

Mortality - Sample Attrition; some Subjects Withdraw from Experiment

New Questions aboutWomen are InterpretedDifferently from EarlierQuestions.

Control Group and Experimental Group IsSelf-Selected GroupBased on Preference forSoft Drinks

Subjects in One Groupof a Hair Dying Study Marry Rich Widows and move to Florida

HOW CAN INTERNAL VALIDITY HOW CAN INTERNAL VALIDITY BE INCREASE?BE INCREASE?

• Control Group

• Random Assignment

• Pretesting and Posttesting

• Posttest Only

Increasing Internal ValidityIncreasing Internal Validity

WHAT ARE THE DIFFERENT BASIC WHAT ARE THE DIFFERENT BASIC EXPERIMENTAL DESIGNS?EXPERIMENTAL DESIGNS?

• One Shot Design (After Only)

• One Group Pretest-Posttest

• Static Group Design

Quasi-Experimental DesignsQuasi-Experimental Designs

ONE SHOT DESIGN (AFTER ONLY)

X O1

One Group Pretest-Posttest

O1 X O2

Static Group Design

Experimental Group X O1 Control Group O2

• Pretest - Posttest Control Group Design

• Posttest Only Control Group

• Solomon Four Group Design

Three Good Experimental DesignsThree Good Experimental Designs

Pretest-Posttest Control Group Design

Experimental Group O1 X O2

Control Group O3 O4

Posttest Only Control Group

Experimental Group R X O1

Control Group R O2

Solomon Four Group Design

Experimental Group 1: R O1 X O2

Control Group 1: R O3 O4

Experimental Group 2: R X O5

Control Group 2: R O6

Chinese Food Study Traditional Choice Studies

Choose one from several (e.g. One meal from three, or none of the above)

Paid to participate, regardless of answers

Incentive Choice Study Choose one from several, chance you

will have to live with your choice Get $ - cost of a meal + meal

Chinese Food Study Pilot Study

41 Participants. Study conducted in BAB classroom. All choose some meals during regular

choice task. 21 did not choose a meal, when they

had to pay.

Chinese Food Study Actual Study

108 Participants. Study conducted in New China Town

Restaurant. All but 8 choose a meal in final task. Data more informative, can predict

better, when participants have to live with their choices.

Chinese Food Study

Attribute Levels

Soup No Soup Hot & Sour Soup Egg Drop Soup Rice/Noodle White Rice Brown Rice Noodles

Sauce

Brown Sauce Szechuan Sauce (Hot and Spicy)

Sweet and Sour Sauce

Vegetables

No Vegetables Standard Vegetables* Tofu & Exotic Vegetables**

Meat No Meat Beef Chicken Shrimp Spring Roll Vegetable Spring Roll Pork Spring Roll

Quantity Pint Quart (2 Pints) Price $3.99 $4.99 $5.99

* Standard Vegetables: (Includes common vegetables that you would find in a supermarket, e.g. broccoli, green peppers, green beans, mushrooms, snow peas, …) ** Exotic Vegetables: (Includes vegetables usually found in Asia, e.g., bamboo shoots, Shanghai Bokchoy, Green Mustard, Chinese egg

Chinese Food Study

Choice Set 1

Attributes Meal 1 Meal 2 Meal 3 Soup Hot & Sour Hot & Sour Hot & Sour

Rice/Noodle Noodles White Rice Brown Rice Sauce

Brown Sauce

Szechuan Sauce Sweet and Sour

Sauce Vegetables

No Vegetables

Standard

Vegetables Tofu & Exotic

Vegetables Meat No Meat Beef Chicken

Spring Roll Vegetable Pork Pork Quantity Pint Pint Quart

Price $3.99 $5.99 $5.99 Please indicate which meal you would choose (circle your choice).

Meal 1 Meal 2 Meal 3 None of the Above

Chinese Food StudyDescription of Possible Meals

Attributes Meal 1 Meal 2 Meal 3 Meal 4 Meal 5 Meal 6 Meal 7 Meal 8 Meal 9 Meal 10

SOUP None Hot & Sour

Soup Egg Drop

Soup None

Hot & Sour Soup

None None Egg Drop

Soup Hot & Sour

Soup Egg Drop

Soup

Rice/Noodles Brown Rice

Brown Rice

Noodles Brown Rice

Brown Rice

White Rice Brown Rice

White Rice Noodles White Rice

Type of Sauce Brown Sauce

Sweet and Sour Sauce

Brown Sauce

Sweet and Sour Sauce

Brown Sauce

Brown Sauce

Szechwan Sauce

Sweet and Sour Sauce

Sweet and Sour Sauce

Szechwan Sauce

Type of Vegetables

Tofu & Exotic

Vegetables

No Vegetables

Standard Vegetables

Tofu & Exotic

Vegetables

Standard Vegetables

Tofu & Exotic

Vegetables

Standard Vegetables

Standard Vegetables

Tofu & Exotic

Vegetables

Standard Vegetable

s

Type of Meat No Meat Shrimp Chicken Shrimp Shrimp Beef Beef Shrimp Shrimp No Meat

Spring Roll Pork

Spring Roll Vegetable

Spring Roll Vegetable

Spring Roll Vegetable

Spring Roll Pork

Spring Roll Vegetable

Spring Roll Vegetable

Spring Roll Vegetable

Spring Roll Pork

Spring Roll

Vegetable Spring Roll

Quantity Pint Quart Quart Pint Pint Quart Quart Quart Pint Quart

Price $4.99 $5.99 $4.99 $5.99 $4.99 $3.99 $4.99 $5.99 $3.99 $4.99

Chinese Food StudyDescription of Possible Meals

Attributes Meal 11 Meal 12 Meal 13 Meal 14 Meal 15 Meal 16 Meal 17 Meal 18 Meal 19 Meal 20

SOUP Hot & Sour

Soup Hot & Sour

Soup None

Egg Drop Soup

Hot & Sour Soup

None Egg Drop

Soup Hot & Sour

Soup Hot & Sour

Soup None

Rice/Noodles White Rice White Rice Noodles Noodles Brown Rice

White Rice Noodles Noodles Noodles Noodles

Type of Sauce Brown Sauce

Szechwan Sauce

Szechwan Sauce

Brown Sauce

Sweet and Sour Sauce

Brown Sauce

Sweet and Sour Sauce

Brown Sauce

Szechwan Sauce

Sweet and Sour Sauce

Type of Vegetables

Tofu & Exotic

Vegetables

Tofu & Exotic

Vegetables

No Vegetables

Standard Vegetables

Tofu & Exotic

Vegetables

Standard Vegetables

Standard Vegetables

No Vegetables

Tofu & Exotic

Vegetables

Tofu & Exotic

Vegetables

Type of Meat Beef Shrimp Beef Beef Shrimp No Meat Chicken Beef Chicken No Meat

Spring Roll Vegetable

Spring Roll Pork

Spring Roll Pork

Spring Roll Pork

Spring Roll Vegetable

Spring Roll Vegetable

Spring Roll Vegetable

Spring Roll Pork

Spring Roll Pork

Spring Roll Vegetable

Spring Roll

Quantity Pint Pint Pint Quart Quart Pint Pint Quart Quart Pint

Price $3.99 $4.99 $3.99 $5.99 $5.99 $3.99 $3.99 $4.99 $5.99 $4.99

Chinese Food Study (Results)

Top Choice* Top Two Choices** Model No. Correct Total No. Percentage No. Correct Total No. Percentage ICC 13 27 48.14 16 27 59.26 HCC 7 27 25.93 7 27 25.93 ICVM 4 27 14.81 6 27 22.22 HCVM 2 27 7.41 7 27 25.93

* predicting top choice from 21 possible alternatives * *predicting either top choice or second choice from 21 possible alternatives

Chinese Food Study (Results)

Summary of Parameter Estimates for Random Effects Logit Analysis

Parameter Intercept Hot &Sour

Soup Egg Drop

Soup Brown Rice*

Noodles*

Szechwan Sauce**

Sweet &Sour Sauce**

ICC Slope (Mean) 2.62 -0.76 0.43 0.28 0.42 -0.17 0.01 Slope (Std) 0.65 0.59 0.47 0.48 0.54 0.59 0.52 Slope (Het) 0.82 7.15 3.11 0.99 1.18 4.91 3.13

HCC Slope (Mean) 0.67 0.56 0.55 0.58 -0.09 0.38 0.14 Slope (Std) 0.57 0.45 0.50 0.52 0.52 0.41 0.36 Slope (Het) 1.55 1.58 3.46 3.05 3.44 1.78 0.89

* with respect to White Rice. ** with respect to Brown Sauce.

Summary of Parameter Estimates for Random Effects Logit Analysis

Parameter Standard

Vegetables Exotic

Vegetables Beef

Chicken

Shrimp

Pork Spring

Roll* Quart

Price

ICC Slope (Mean) 1.46 0.23 2.66 3.42 2.48 -0.60 0.40 -1.59 Slope (Std) 0.44 0.52 0.49 0.64 0.61 0.47 0.39 0.19 Slope (Het) 1.02 2.99 2.07 6.14 5.44 3.74 1.26 0.44

HCC Slope (Mean) 1.85 1.00 3.65 4.11 3.28 -0.80 1.29 -0.99 Slope (Std) 0.44 0.55 0.91 0.93 0.91 0.51 0.46 0.26 Slope (Het) 0.49 3.84 1.76 2.68 4.53 2.90 2.93 0.20

* with respect to Vegetable Spring Roll.

TEST MARKETINGTEST MARKETING

EXPERIMENTAL PROCEDURE OPPORTUNITY TO TEST A NEW PRODUCT NEW MARKETING PLAN UNDER

REALISTIC MARKET CONDITIONS

MEASURE SALES OR PROFIT POTENTIAL.

SELECTING A TEST MARKETSELECTING A TEST MARKET

POPULATION SIZE DEMOGRAPHIC COMPOSITION LIFESTYLE CONSIDERATIONS COMPETITIVE SITUATION MEDIA SELF-CONTAINED TRADING AREA SECRECY

CONTROL METHODCONTROL METHOD OF TEST MARKETING OF TEST MARKETING

SMALL CITY LOW CHANCE OF BEING DETECTED DISTRIBUTION IS FORCED (GUARANTEED)

ADVANCED EXPERIMENTAL DESIGNSADVANCED EXPERIMENTAL DESIGNSARE MORE COMPLEXARE MORE COMPLEX

COMPLETELY RANDOMIZED

RANDOMIZED BLOCK DESIGN

LATIN SQUARE

FACTORIAL