A control variable can be anything that symbolizes constant or limited in a research study. It is a variable that is not only used for the study’s aim but is also controlled by the experiment. Therefore, control variables could influence the investigation and its outcome. This is an ideal control variable definition. An investigation has various types of variables, including a control variable or controlled variable. Variables are just values that can change with time. An ideal investigation has two changing variables- one is the independent variable, and the second is the dependent variable. For example, suppose you are experimenting on what is the amount of light received affect plants growth?
In this case, the amount of light is changed by you is called the independent variable.
As one changes the independent variable, you watch what happens to the dependent variable. In this case, you see how much the plant grows.
Undeniably a control variable is another factor in any experiment; it must be held constant. For example, take the plant growth experiment. This may be factors like water, fertilizer amount, and others.
If you don’t change the variables throughout the study- it will hold an identical outcome depending on the constant variable. Controlling here means changing the room temperature. This may be controlled indirectly through various statistical control or randomization.
Control variable example:
Q. Does soil qualify affect plant’s growth?
A: The control variables are the amount of light, water, and temperature.
Q. Does caffeine improve memory recall?
A: The control variable is types of memory test, participant age, noise in the environment.
Q. Do people with a fear of spiders perceive spider images faster than other people?
A: The control variables are 3D or 2D picture, screen brightness, room light, visual stimuli size, etc.
Why are control variables important?
Control variables increase the internal rationality of an experiment by limiting the influence of perplexing and other peripheral variables. This helps you create a correlational or causal relationship between your variables of interest.
Apart from the independent and dependent variable types, all variables that can influence the results should be controlled. If you don’t control relevant variables, one may not demonstrate or establish that they didn’t affect your outcomes. Uncontrolled variables are alternative explanations for your products.
Experiments and control variables:
When experimenting, a researcher is interested in knowing the effect of an independent variable. Unfortunately, it only depends on the dependent variable. Control variables provide you the results that are exclusively caused by your experimental operation.
Example with Experiment
Suppose you get an experiment that searched for the effectiveness of Vitamin D supplements on improving attentiveness. You program an investigation with a local group that receives a placebo tablet and an experimental group that receives the supplements. The independent variable is whether the vitamin D addition is added to a régime, and the dependent variable is the level of alertness.
To make sure any change in awareness is caused by the vitamin D complement and not by other influences, you control these variables that might affect alertness:
Timing of your breakfast, meals, and dinner
Caffeine or alcohol intake
Control variables and non-experimental research
In non-experimental research, you can’t operate the independent variable. It happens due to ethical or practical considerations. In its place, control variables are restrained. It is also taken into account to infer relations between the main variables of interest.
Comparison between control variable and control group
A control group is not the same as a control variable. Control variables can be measured with a constant parameter. You can get throughout the study for both experimental and control groups. When independent variable lies between the experimental groups and control groups.
A control group doesn’t go through the experimental treatment of interest, and its results are compared with those of the experimental group. A control group doesn’t hold any treatment, a standard treatment that’s already widely used, or a fake treatment.
Apart from the research treatment, everything in an experimental procedure should be the same between the control and experimental groups.
Methods to control a variable
There are various ways to control variables in experimental designs. Some of these can be used in observational techniques:
Random assignment producers
In experimental studies with various groups, accomplices should be randomly assigned to diverse conditions. Random assignment helps you balance the characteristics of groups. Moreover, it allows you to keep the balance and ensure no systematic differences between them.
This method of assignment controls member variables that might otherwise vary between groups and twist your results.
You can measure and control for superfluous or extra variables statistically to remove their effects on other variables.
Controlling for a variable means designing control variable data and independent and dependent variable information in regressing analysis. That way, you can distinguish the control variable’s effect.
It’s vital to use the same procedures across all groups while doing the same experiment. The groups should only fluctuate in the independent variable manipulation. Thus it can separate its effect on the dependent variable as the results.
You can hold control variables constant at a static level using a design procedure for all participant meetings. For example, the instructions and time spent on an experimental task should be the same for all contributors in a laboratory setting.
Before doing any experiment with control variables and independent variables, make sure you know all these mentioned factors and definition thoroughly. These theoretical knowledge will guide you in various experimental procedures. If you have any confusion, talk to your science teacher before starting your experiment or science assignment. In this blog, we have discussed a piece of detailed information about control variables and examples. Hope this blog will help you in your studies and assignments.