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Experimental Research| What is it, Types and Examples

Updated: Jul 10

Think back to basic science experiments you may have conducted as a child, such as growing plants under different light conditions to observe growth differences.

These simple experiments involve manipulating one variable while keeping others constant, allowing you to observe the effects of that manipulation. This fundamental approach lays the groundwork for more complex experimental research.

Experimental Research 

Experimental research is a quantitative research method where researchers manipulate one or more independent variables to measure their effect on dependent variables.This approach offers a methodical technique to test theories and identify causal relationships.

Since childhood, many of us have engaged in simple scientific experiments, from mixing baking soda and vinegar to create a volcanic eruption to observing plant growth under different conditions. These early experiments are rooted in the principles of experimental research design, which provides a structured approach to inquiry and discovery.

An experimental research ensures that researchers can systematically investigate their hypotheses and obtain reliable, reproducible results.

In this article, we will explore the essential components of experimental research, common types of experimental research and examples in detail for effectively structuring your research study.

Purpose and Suitability of Experimental Research 

Experimental research is most effective for exploring cause-and-effect relationships, rather than for descriptive or exploratory research.This method is ideal for situations involving a limited number of independent variables that can be manipulated or controlled. 

Types of Experimental Research 

There are two primary categories of experimental research designs: quasi-experimental designs and true experimental designs.

True experimental designs

True experimental designs involve the manipulation of one or more independent variables by the researcher, with participants randomly assigned to different treatment groups. This randomization helps control for confounding variables, ensuring any observed differences between groups are due to the independent variable manipulation alone.

Key Features

Key features of true experimental designs include:

Random assignment: Random assignment helps to account for potential confounding variables by guaranteeing that each participant has an equal probability of being placed in any group.

Control group: This group serves as a baseline against which to measure the impact of the independent variable and is frequently utilized for comparison with the experimental group receiving the course of treatment.

High internal validity: True experimental designs are very successful in determining the causes of various variables because they allow for control over extraneous variables and random assignment.

Quasi-experimental designs

Quasi-experimental designs also involve manipulating an independent variable, but participants are not randomly assigned to treatment and control groups. This makes quasi-experiments more practical in real-world settings where random assignment is not feasible.

Key Features

 Key features of quasi-experimental designs include:

Non-Random Assignment: Participants are divided into groups according to standards other than the random selection process, which could lead to selection biases.

Practicality: Helpful in real-world situations or when interacting with groups that already exist, like those in offices or classrooms.

Moderate Internal Validity: Compared to actual experiments, quasi-experiments are more prone to confounding variables, although they are nevertheless valuable for analyzing causal links .

Non-Experimental Research

Non-experimental research is a type of study that does not involve the manipulation of an independent variable or the random assignment of participants. Instead, it focuses on observing and measuring variables as they naturally occur.

Key Methods of non experimental research

1. Survey Research: This method collects data through questionnaires or interviews to gather information about people's attitudes, behaviors, or characteristics.

2. Observational Studies: This involves observing subjects in their natural environment without any manipulation by the researcher.

3. Correlational Studies: This type of study examines the relationship between two or more variables to determine if a correlation exists, but it does not imply causation.

Key Features of Non Experimental Research

1. Broader Scope: Non-experimental research allows for the study of a wide range of variables and relationships in natural settings.

2. Flexibility: It is more adaptable to various research contexts and can be applied to a wide range of subjects and environments.

3. Lower Causal Inference: Non-experimental research lacks the ability to establish causal relationships due to the absence of manipulation and control.

By understanding these types of research, researchers can choose the most appropriate method based on their study goals, the feasibility of random assignment, and the level of control required over extraneous variables.

Settings for Experimental Research

Laboratory Experiments

Controlled Environment : Laboratory experiments are carried out in carefully regulated settings that are frequently developed for specific studies. This eliminates outside interference and enables researchers to carefully alter independent variables and evaluate their effects on dependent variables.

High Internal Validity: In terms of determining cause-and-effect relationships, the controlled environment ensures that the results are extremely reliable as well as precise. Extraneous variables can be reduced or deleted to maximize internal validity.

Reduced External Validity: However, because laboratory tests are artificial, it's possible that the results won't translate well to other contexts. Lower external validity can arise from the environment's inability to accurately reflect the complexity and variability of natural settings.

Field Research

Real-World Environments: In natural, real-world environments like workplaces, schools, or communities, field experiments are carried out. Consequently, the results are more applicable and flexible in real-life situations.

High External Validity: Field experiments typically possess a high degree of external validity because of their real-world environment. The results are more likely to be representative of real-world actions and outcomes in natural settings and to be generalizable.

High Internal Validity Despite Difficulties: Field experiments encounter difficulties in maintaining internal validity, including managing unrelated factors and guaranteeing uniform treatment administration in various contexts. They are less prevalent than laboratory experiments because of their complexity.

Practical and Moral Points to Remember: A number of practical and ethical considerations, including securing approvals, managing unforeseen circumstances, and guaranteeing participant safety and well-being, must be carefully considered while conducting field experiments.

Benefits of Experimental Research 

Internal Validity: Researchers are able to conclude cause and effect with confidence when controlled conditions and random assignment are used to attain high internal validity.

Explanatory Focus: Experimental designs are ideal for investigating cause-and-effect interactions in explanatory research.

Control Over Variables: Offers a methodical way to work with and manage independent variables.


Examples of True Experimental Research 

In true experimental research the participants are assigned at random to either the treatment or control groups. For example, a study investigating how well a novel blood pressure-lowering drug works can be set up as a real experiment. Random assignment is used to assign participants to receive the medication or a placebo. After making sure that all other factors are under control, researchers test blood pressure readings before and after the intervention to assess how effective the medication is.


Examples of Quasi Experimental Research 

A quasi-experiment lacks random assignment but still involves an intervention.Researchers might look into how a novel teaching strategy affects student performance in a particular classroom. Random assignment isn't possible because students are already organized into classes. Researchers have the option to assess this class's performance both before and after the new approach is implemented, or they can assess it against a comparable class that was not taught using the new strategy.


Experimental research is a vital methodology for understanding causality by manipulating variables in controlled settings. This approach is widely applicable across various fields and is particularly prevalent in the physical sciences. The main advantage of experimental research is its capacity to establish cause-and-effect relationships through systematic control of independent variables and observation of their effects on dependent variables.

Experimental Research can be of Laboratory experiments, where conditions are tightly controlled, and field experiments, which take place in natural settings. Laboratory experiments are beneficial for isolating variables and establishing causality, while field experiments offer greater external validity by reflecting real-world conditions.

In short, experimental research offers a potent tool for researchers to test hypotheses and draw dependable conclusions about causal relationships, significantly contributing to scientific knowledge and practical applications.


What is experimental research?

Experimental research is a scientific study consisting of two variables, one of which is independent variable while the other is independent variables. The main objective of experimental research is to establish cause and effect relationships between variables. 

What are the key components of experimental research?

Experimental research design consists of the following four components including: hypothesis, treatments, units and the assignment methods.

What are experimental research methods?

Experimental methods are research designs that intentionally introduce exogenous variation in the intervention assignment to make causal inferences. These methods usually involve randomized variation of programs or interventions that are directly controlled by the researcher.

What are the main differences between experimental and non-experimental research?

In experimental research, the independent variable is entirely within the researcher's control, and it can be changed to test a hypothesis. While in non experimental research, this kind of control is not available to the researcher, thus they are forced to rely on measurements and observations of naturally occurring variables.


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