Step 3: Operationalizing Your Variables

Instructions: Click on the sections below to see the explanations.

Now that you know what your research hypothesis is, your next step is to decide how your experiment will be testing it. Although you are replicating a previous study, you might want or have to modify and simplify it.

Simplifying the Original Study (Click)

Your IA should be a simple experiment that:

  • Creates two different conditions by manipulating one independent variable.
  • Measures one dependent variable per participant in each condition.

If you are using one of the recommended studies, the variables can be found in the “Participants and Procedures” section.

NB. If the study that you are replicating has more than one IV and/or or more than two conditions, you should simplify it so that you only create two different conditions by manipulating one independent variable. The “IA Tip” section of the original study can help you with suggestions.

Depending on the study, the two conditions might be:

  • An experimental condition characterized by the presence of the independent variable.
  • A control condition characterized by the absence of the independent variable.

For instance, participants might be asked to memorize a list of words either while listening to music with lyrics or not (independent variable), and then have their memorization tested (dependent variable).

Or they might be:

  • A first experimental condition characterized by a certain degree or form of the independent variable.
  • A second experimental condition characterized by another degree or form of the independent variable.

For instance, participants might be asked to study a list of words either while listening to music with extensive lyrics or while listening to music with very limited lyrics (independent variable), and then have their memorization tested. In this case, each condition serves as the control for the other one.

Operationalizing the Independent Variable (Click)

Either way, to create these two conditions, you have to decide how to manipulate the independent variable. Describing how you will do so is called “operationalizing” the independent variable, because it details how you will operate to manipulate the factor under investigation and create two different conditions.

NB. Your operationalization of the IV can be different from the original study. You can modify/simplify it, e.g., by changing the task that participants have to perform, or the stimulus on which they have to perform it. You simply have to make sure that you are still manipulating the relevant independent variable for your experiment.

Operationalizing the Dependent Variable (Click)

To compare participants’ behavior in the two conditions, you have to decide how to measure their performance of the task they were instructed to complete. Describing how you will do so is called “operationalizing” the dependent variable because it details how you will operate to measure the behavior under consideration by using a specific instrument and a specific unit of measurement.

NB. Again, your operationalization of the DV can be different from the original study. You can modify it and make it more simple as long as it still measures the relevant dependent variable for your experiment. Importantly, you should make sure that you will obtain a numerical value for each participant in each condition. Although authorized for the IA, we do not recommend that your DV yield nominal data. Likewise, your DV should not be a percentage of participants per condition (e.g., “25% of participants in the experimental condition answered ‘Yes’”).

Meeting Ethical Standards (Click)

As you decide how to manipulate the independent variable and measure the dependent variable, keep in mind that:

  • To be accepted as an IA, your experiment can NOT involve deception or harm (be it physical or psychological, including conformity, deprivation, or any kind or ingestion). 
  • You may also not study animals or children (participants under the age of 16 will need parental consent). 
  • Regarding deception, you do not have to give full disclosure to your participants, but you may not lie to them or use unnecessary or extensive deception.
Online Experiments (Click)

If you have to conduct your experiment online, make sure that the way you plan on manipulating the independent variable and measuring the dependent variable are technically possible and realistic digitally, (for instance during a Google Meet video call, using Google Slides and Google Form). This guide will give you more directions to help you conduct your experiment online later on.

QUESTIONS: Click on the questions below to see the worked examples.

Answer all questions below on your individual Experiment Creation Form.

Question 8: How will you operationalize the independent variable in your experiment? (Click)

Your answer should indicate how you will make one of the following different between the two conditions:

  • The task that participants have to perform.
  • OR The stimulus on which they are operating this task.
  • OR The environment in which they are performing the task.

Table 5: Example of Operationalized Independent Variable

Question 9: How will you operationalize the dependent variable in your experiment? (Click)

Your answer should indicate:

  • The instrument that you will be using 
  • The unit of measurement that you will be using

Table 6: Example of Operationalized Dependent Variable