# Independent and Dependent Variables: Which Is Which?

One variable is called the independent variable, the other is called the dependent variable. But what about that third type of variable used in scientific experiments? It is the control variable, also known as the constant variable.

Therefore, the aim of the tutor’s investigation is to examine whether these independent variables – revision time and IQ – result in a change in the dependent variable, the students’ test scores. However, it is also worth noting that whilst this is the main aim of the experiment, the tutor may also be interested to know if the independent variables – revision time and IQ – are also connected in some way. After you have done the experiment part of your Science Fair Project, you will most likely have some data that you recorded (for example, time and distance). In most situations, you will have two variables that you are comparing.

It’s what changes as a result of the changes to the independent variable. An example of a dependent variable is how tall you are at different ages.

## Independent vs Dependent Variables

The political party and policies of the status quo were changed, and a new governing coalition installed which would rule for decades until the next critical election. The theory of critical elections fit well with what scholars knew about generational effects and the emerging literature on “major shocks” as a variable in determining the existence, direction, and strength of partisanship. It also helped explain the radical shifts in national politics which occurred irregularly in American history. Scholars also hypothesized that realigning elections rejuvenated public support for the political system, which helped explain the relative stability of American political structures. The concept of “secular realignment” was developed to account for gradual shifts in politics which had similar effects (eventually) to a critical realigning election.

### How do you define dependent and independent variables?

An independent variable is defines as the variable that is changed or controlled in a scientific experiment. Independent variables are the variables that the experimenter changes to test their dependent variable. A change in the independent variable directly causes a change in the dependent variable.

For more than half a century, the concept of a realigning election—a dramatic shift in the electoral coalition supporting the existing political system—has been an important one in political theory. First enunciated by V. O. Key, Jr. in 1955, the theory of realigning elections suggested that certain “critical elections” created sudden, massive shifts in the electorate.

As an example, you are interested in how stress affects heart rate in humans. Your independent variable would be the stress and the dependent variable would be the heart rate. You can directly manipulate stress levels in your human subjects and measure how those stress levels change heart rate.

This variable is the one that is manipulated or changed by the scientist. The second type of variable is the one that is observed or measured in the experiment, and it is known as the dependent variable.

In experimental studies, where the independent variables are imposed and manipulated, the dependent variable is the variable thought to be changed or influenced by the independent variable. Split-ticket voting and issue-oriented voting increase, leading to political volatility. Divided government (one party controls the executive branch, while another controls the legislature) becomes the norm. More recently, scholars focused on self-identification as a good measure of a person’s political independence. The value of self-identification as a measure of a person’s political independence or partisanship is that it is seen as a proxy for the behavior which should be exhibited by the independent voter.

• For more than half a century, the concept of a realigning election—a dramatic shift in the electoral coalition supporting the existing political system—has been an important one in political theory.
• The political party and policies of the status quo were changed, and a new governing coalition installed which would rule for decades until the next critical election.

The independent variable is the variable that you have control over, what you can choose and manipulate. It is usually what you think will affect the dependent variable. In some cases, you may not be able to manipulate the independent variable. It may be something that is already there and is fixed, something you would like to evaluate with respect to how it affects something else, the independent variable like color, kind, time.

You can remember this because the observation or measure of the dependent variable will change as the independent variable is altered. In experiments, you have to test one independent variable at a time in order to accurately understand how it impacts the dependent variable. The outcome variable measured in each subject, which may be influenced by manipulation of the independent variable is termed the dependent variable.

For each of the independent variables above, it’s clear that they can’t be changed by other variables in the experiment. You have to be the one to change the popcorn and fertilizer brands in Experiments 1 and 2, and the ocean temperature in Experiment 3 cannot be significantly changed by other factors. Changes to each of these independent variables cause the dependent variables to change in the experiments. The dependent variable (sometimes known as the responding variable) is what is being studied and measured in the experiment.

As the name suggests, it is the variable that the scientist wants to remain the same. Often, there is more than one control or constant variable in a scientific experiment.

## Independent Variable Definition

The dependent variable (height) depends on the independent variable (age). Independent variables are the variables that the experimenter changes to test their dependent variable. A change in the independent variable directly causes a change in the dependent variable. The effect on the dependent variable is measured and recorded.

## Understand the Independent Variable in an Experiment

Now, let’s talk about those three types of variables used in scientific experiments. The first variable type is called the independent variable.

Some studies concluded that “secular realignment” came in short, jerky, periods called “punctuations.” Initially, the concept of a realigning election was monolithic, that is, the effects were believed to be national in effect. But beginning in the 1980s, political scientists began to conclude that realigning elections could occur on sub-national levels (such as regions or even within states).

The scientist will want to observe these control variables as much as the dependent variable. The reason is that if the control variables aren’t held constant, the scientist will not know if the independent variable caused the change in the dependent variable or if the change was due to the control variable.