Designul unui experiment.

I. INTRODUCTION

You have been exposed to a lot of research in this course, but this is your opportunity to think more

strategically about how it is done. You probably dont have much (or any) experience designing

experiments. And thats okay! This document is here to familiarize you with the process, explain some

key terms, and prepare you for the assignment. If you follow these steps and stick to the rubric, you

will be great!

II. HOW TO DESIGN AN EXPERIMENT

Step # 1: Review the Literature

First, choose a topic. Do a review of the scientific literature on that topic to figure out what other

researchers have already found. If youre not sure where to start, just search for a topic that interests

you using Google Scholar. For example, if you search for ikea effect, you might see something like

this:

You dont need to spend too much time on the literature review, and you definitely dont need to

become an expert on your topic for this assignment. However, you should get a feel for the kinds of

research that have been done in your area of interest.

As youre reading about your topic, think about what questions interest you and how you might

approach them. For example, you could propose a follow-up experiment to just one specific study, or

you could do an extensive review of all the literature and propose an experiment that contributes to

the overall theory. Make sure that your exact experiment or idea isnt already published, and that it

contributes to the existing literature. It is up to you to decide where you want to take this just

remember to have fun while youre at it!

Example: Your review of the literature might teach you that the IKEA effect shows that consumers are

willing to pay more for self-created products than identical products created by others.

Step # 2: Establish a clear research question

The research question summarizes the goal of your study. What are you trying to test? Does your

research question stem from the background literature?

Your research question should be specific and concise, and address just one topic or goal; dont try to

explore too many questions or a broadly defined topic because will just complicate your research and

make it much harder to determine what you are really testing. For this project, you could propose a

follow-up experiment to just one published study, or do an extensive review of the literature on your

topic of choice and propose an experiment that contributes to the overall theory but whatever

approach you take, you should have just one research question and just one experiment. So

remember: Keep it simple, but interesting!

Example: Is the overvaluation of self-made products (IKEA effect) driven by feelings of competence?

(And is it specifically due to competence, or could it be an effect of feeling happier overall?)

Step # 3: State the hypothesis to be tested

Formulate a hypothesis that can be tested with your experiment. What do you think will happen in

your experiment? Some people call a hypothesis an "educated guess," but good scientists never guess.

Your hypothesis is basically a prediction based on the background information that you have on the

topic.

Example: I hypothesize that the overvaluation of self-made products (IKEA effect) is driven by feelings

of competence, but not driven by an overall positive mood.

Step # 4: Design your experiment

Your design will depend on what you want to test and for every research question, there are many

ways to test it.

Dont worry about which exact scales you would use (i.e., it is enough to say that you want to measure

mood with a questionnaire, you do not need to specify that you would use the Positive and Negative

Affect Schedule) or how the data would be analyzed (i.e., we dont expect you to have a background

in statistics!).

Questions that you should ask yourself while designing your experiment:

What is your paradigm? How many experimental conditions? Are participants randomly assigned?

Is it within-subjects and/or between-subjects? (Do different groups get different treatments, or

does the same group get two different treatments?)

What are your independent and dependent variables?

Is there a control group? What are you comparing?

Does your experiment have construct validity?

Does your experiment have internal validity?

Does your experiment have external validity?

Example: In this study, participants are randomly assigned to either build a product (Condition 1) or

are given a finished product that they are asked to examine (Condition 2). Because the two conditions

are independent samples that receive different treatments, the experiment is between-subjects. Then,

in a survey, we elicit participants' willingness to pay for the product, the feelings of competence

associated with the product, and participants' overall mood. These three measures are the dependent

variables, which we will look at to determine whether there is any effect of the independent variable.

Independent variable: Condition 1 (builders) or Condition 2 (non-builders)

Dependent variables: 1) participants' willingness to pay for the product, 2) the feelings of competence

associated with the product, and 3) participants' overall mood.

We believe the experiment has construct validity because it assesses feelings of competence in order

to make claims about the level of this feeling in relation to the IKEA effect. We believe that it also has

internal validity because the experimental manipulation appears to cause the outcome of the study.

We can build a stronger case for this if mood does not affect willingness to pay, but the feeling of

competence does (which is our hypothesis). Finally, we believe that the experiment has external validity.

Step # 5: What are the implications?

hink about the implications of your research. What will your findings mean for humanity? Will this

experiment contribute something to the understanding of a particular topic or theory?

Example: The findings of this research will show that self-created products are valued more because

of their influence on feelings of competence. The IKEA effect, therefore, is driven by feelings of

competence. This implies that people may affirm their identities with the feeling of pride when they

successfully create something.

These results have implications both for firms seeking to maximize customer satisfaction and for

individuals seeking to increase their life satisfaction. Disrupting consumers' sense of competence

increases consumers' desire to engage in co-creation, but absent this manipulation, they are very

unlikely to assemble their own product. Moreover, involving consumers in co-creation is not without

risks. Although consumers may attribute successful co-creation experiences to their own efforts, they

may attribute co-creation failures to the firm, which negatively impacts consumers' perceptions of a

firm (Bendapudi & Leone, 2003). Future research should examine the best way to encourage

consumers to co-create.

Finally, the overvaluation of products that occurs as a result of the IKEA effect has broader implications

for organizations because overvaluation contributes to two key organizational pitfalls: sunk cost effects

(Arkes and Blumer, 1985, Biyalogorsky et al., 2006 and Staw, 1981), which can cause managers to

continue to devote resources to failing projects they have previously invested in (Biyalogorsky et al.,

2006), and the not invented here syndrome, in which managers refuse to use perfectly good ideas

developed elsewhere in favor of their, sometimes inferior, internally developed ideas. Our results

suggest that managers may persist in pursuing failed projects and concepts because they truly believe

that their ideas are more valuable; not pursuing their ideas means that money is left on the table and

that using a competitor's ideas would simply be choosing an inferior option.

Step # 6: Review Step 1 to Step 5

he review phase is very important because you need to make sure that your design is consistent with

the research idea and hypothesis. Ask yourself whether you will be able to answer your research

question with your experimental design. Ask whether your findings will be meaningful in the real

world.

You may have noticed that our examples are taken from Experiment 1 in a published study:

Mochon, D., Norton, M. I., & Ariely, D. (2012). Bolstering and Restoring Feelings of Competence via the IKEA Effect. Intern. J. of Research in Marketing, 29, 363369.

We used this example so that you can look up the paper for more details; however, it is very important that your essay is NOT copied from research that has already been published.

III. GLOSSARY

Between-subjects: Participants are separated into independent groups (conditions) and each group

is exposed to different treatments.

Construct validity: Does your experiment test what it is attempting to test?

Controls: These are factors that will NOT CHANGE in the experiment.

Dependent variable: This is the factor that will change because the researchers changed something

in the experiment (independent variable).

Experimental and Control Groups: These are the groups in the experiment. The control group has all

factors held constant - no variable is introduced. In the experimental group, the manipulated variable

is introduced. Experiments usually have only one control group, but can have more than one

experimental group. Some experiments do not have a control group, but all experiments have more

than one condition.

External validity: Are the results generalizable? Will the results apply to other situations outside of

the experimental context?

Hypothesis: Describes the expected results in a clear statement.

Independent variable: These are the factor(s) that the researcher will change in the experiment.

Internal validity: Did the experimental manipulation cause the outcome of the study?

Random assignment to condition: Participants all have exactly the same chance of being put in one

condition as they do in another condition.

Within-subjects: Participants are exposed to all the different treatments.