What is Experimental Research Design? Definition, Examples, and Types of Designs

Experimental research is a scientific method that helps prove the relationship between dependent and independent variables. This type of research is used to establish a cause-and-effect relationship between the variables and also to test hypotheses. In a typical experimental research design, the independent variables are manipulated to assess their influence on the dependent variables. The strength of the association is ascertained by the degree to which a change in the independent variable changes the dependent variable. 

Experimental research uses statistical analysis of quantitative data and, therefore, has a high degree of accuracy. This research type is common in various fields, including psychology, economics, education, healthcare, etc. Experimental research designs are of three types—pre-experimental, quasi-experimental, and true experimental. 

In this article, we’ll take a deep dive into defining experimental research and understanding the importance and uses of the different types of experimental research designs in various industries through some examples.  

What is Experimental Research? 

Experimental research1 definition is that it is a type of study in which one or more independent variables are manipulated (as the intervention or treatment) by the researcher, participants are randomly assigned to different groups (treatment or control), and the effects of these interventions on the dependent variables help determine the causality between the variables. Thus, experimental research design is most appropriate in exploratory research wherein the objective is to establish cause-and-effect relationships.  

Experimental research can be conducted in both laboratories and field settings. In laboratories, the experiments have high internal validity (the extent to which a study can establish a cause-and-effect relationship between variables) but low external validity (generalizability) because the artificial settings in laboratories cannot replicate real-world conditions and, therefore, the results cannot be generalized. In contrast, field experiments have both high internal and external validity; however, conducting such experiments is time and effort intensive so these are not very common. 

A good experimental research design requires:[2] 

• Good planning to ensure control over the testing environment 
• Appropriate experimental treatments 
• Proper assignment of participants to treatment groups 

Here are a few experimental research examples: 

• Testing a new antibiotic on patients where the treatment group receives the drug and the control group does not. 
• Studying the effects of different fertilizers on plant growth. 
• Studying the influence of various advertising messages and media on participants prior to a product launch. 
• Studying user feedback on new product features in the Software as a Service industry before full-scale implementation. 

Importance of Experimental Research 

So why do we need experimental research? Here are a few reasons:[3] 

• To establish causality

Experimental research helps determine the cause-and-effect relationship between the variables under study. It helps assess whether a change in the independent variable changes the dependent variable. 

• To control variables

Experimental research allows for controlling the effect of extraneous variables. That is, experimental research design can accurately determine if the changes in the dependent variable are indeed caused by the specific independent variable being studied and manipulated. Experimental research reduces the chances of having multiple explanations for the observed changes in the dependent variable. 

• To provide reliable and valid results

Following a structured method while conducting experimental research minimizes the risk of measurement errors and biases. The results are deemed to be more generalizable. 

• To support informed decision-making

Experimental research provides accurate evidence to support informed decision-making by organizations in various operational activities, such as product testing, marketing, etc. 

Types of Experimental Research Designs 

There are three types of experimental research designs:[4] 

Pre-experimental research design 

This experimental research design is used to examine the changes in one or more groups of dependent variables based on a change in the independent variable. This experimental research design can be divided into the following categories: 

• One-shot case study research design: A post-test study of a single set of variables in which a single group is assessed at a single point in time after some treatment is presumed to have caused a change. 

Example: The HR department in a company plans to conduct a training program on learning Microsoft Excel skills for its employees. They conduct a test after one month of training to see if there is any improvement in the employees’ MS Excel skills. 

• One-group pretest-posttest research design: This research design assesses a single set of variables both before and after implementing the intervention, that is, a single group is observed at two time points. Any changes in the outcome are presumed to be the result of the intervention. Considering the same example as above, the employees are tested both before and after the training. Any improvement in employees’ MS Excel skills could be attributed to the training. 

• Static-group comparison: All the groups of variables are divided into two sub-groups, with one sub-group receiving the intervention and the other not receiving it. In the same example, the employees are divided into two groups in which one group (control) does not receive the training while the other group receives it. Both groups are tested and their results compared. Any changes in the MS Excel skills of the treatment group could be attributed to the training. 

Quasi-experimental research design 

In a quasi-experimental research design, participants cannot be randomly assigned to an experimental or control group for practical or ethical reasons. However, in other aspects it resembles a true experimental research design, which is why the name “quasi.” Quasi experiments have high external validity, are useful for smaller sample sizes, are less expensive, and require fewer resources. 

True experimental research design 

In a true experimental research design, participants are randomly assigned to treatment groups and, therefore, have an equal chance of being included in either group. This research design has both control and treatment groups. 

There are three types of true experimental research designs.[5] 

• Posttest-only control group design: Here, the control and treatment groups are not tested before administering the intervention. This type of research is done to avoid affecting the quality or accuracy of the study because a pretest could give participants an idea about the criteria and purposes of assessment, which could bias their responses. However, this method will prevent comparing the outcomes before and after the intervention, thus making it difficult to establish causality. For example, in 1993, Topf and Davis used this research design to examine if critical care unit noise affects REM sleep. 

• Pretest-posttest control group design: Here, testing is done both before and after the intervention is administered. Although this method helps establish the cause-and-effect relationship between variables, the accuracy of the results cannot be guaranteed because of the possible bias based on participants’ exposure to the pretest. For example, Koenig et al. used this research design to study the effect of a yoga program on the classroom behavior of children with autism.  

• Solomon four-group design: Here, participants are randomly assigned to four groups, two of which are control and the other two are the treatment groups. Of these four groups, only one control group and one treatment group undergo pretesting while all four groups undergo posttesting. This method is beneficial because the researcher can observe the differences between the pretest and posttest outcomes and provides more accuracy. Dehghan et al. examined virtual reality technology as a method to reduce anxiety in children undergoing surgery. 

Advantages and Disadvantages of Experimental Research Designs 

Advantages of experimental research designs 

Experimental research designs have a number of advantages. These research designs: [6] 

• Offer researchers a high level of control: The ability to manipulate the independent variable gives researchers a high level of control in the experiment. This can help them easily attribute the results to specific interventions. 
• Provide specific conclusions: The high level of control leads to the results being consistently specific and relevant. 
• Generate results that can be duplicated: These research designs allow duplicating the results when the same variables are manipulated by other researchers. This aspect helps prove the validity of the research because other researchers can verify the published results. 
• Allow cause and effect to be determined: The ability to manipulate variables can help researchers analyze various cause-and-effect relationships. 
• Help in easy replication of natural settings: Conducting experimental research in laboratories can make it easier to replicate natural settings, allowing researchers to have a greater control over extraneous variables. 

Disadvantages of experimental research designs 

Listed below are the main disadvantages of choosing experimental research designs. [1], [3], [4] 

• Risk of errors and bias: These designs have high chances of error and bias because manipulating independent variables is prone to human error, which can skew the observations. 
• High costs and time consumption: Experimental research is cost intensive because it involves large sample sizes and specialized equipment. It is also time consuming because designing the experiment, preparing the tools, conducting the experiment, and analyzing the data require time.  
• Ethical constraints: Experimental research designs include intentionally manipulating the independent variable. If such an intervention could potentially cause harm to human participants by either withholding a proven beneficial treatment or by inducing potentially harmful treatment, then this action would be unethical. 
• Practical and logistic constraints: Some studies may not be practically feasible if they include complex, large-scale, or long-term processes. 
• Artificial settings: Most experimental studies are conducted in highly controlled artificial conditions, such as laboratories, whereas experiments in field settings are relatively rare. In artificial settings, external variables are properly controlled and consequently, the findings may not be generalizable in real-world settings. 

Key Takeaways 

Let’s summarize what we’ve learnt about experimental research in this article. 

• Experimental research is a scientific method that helps establish the cause-and-effect relationship between variables. 
• Researchers have a high level of control over the independent variable and can manipulate it. 
• There is random assignment of participants into groups. 
• There are three types of experimental research designs: pre-experimental, quasi-experimental, and true experimental. 

Frequently Asked Questions 

Q1. What are the differences between experimental and non-experimental research? 

A1. Here are a few differences between experimental and non-experimental research.4 

Q2. How can experimental research help businesses? 

A2. Experimental research can be useful for businesses by helping them make informed decisions to increase operational efficiency.3 Here are a few examples of how this can be used by businesses. 

• Product development and testing 

Experimental research can help companies test new products and features before launching them for public consumption. Experimental research designs can help companies analyze and compare different versions and see which one is better in terms of customer satisfaction, sales, usability, etc.  

• Marketing strategy design 

Businesses can test the impact of various types of marketing channels, messages, and strategies to develop one that has the maximum potential to influence and engage customers. 

• Customer experience strategies 

Experimental research can help companies identify the features that increase customers’ experience while interacting with the company and using their products, including user-friendly website content design, easily available customer service, etc. 

• Pricing strategies 

Experimental research helps companies identify the optimum pricing strategies that could attract and retain more customers and also maximize revenue. 

Q3. What are the important steps in conducting true experimental research? 

A3. Here are the general steps you would need to follow for a true experimental research design.5 

1. Identify the research objective. 
2. Identify the independent and dependent variables. 
3. Define the sample and randomly assign the participants to groups (control and treatment). 
4. Conduct pretests, if required. 
5. Conduct the research or in other words, administer the intervention or treatment to the applicable groups(s). 
6. Conduct posttests after the intervention has been administered. 
7. Analyze and compare all the outcomes to assess the cause-and-effect relationship between the variables. 

Q4. What are experimental research errors and how can they be avoided?7 

A4. Experimental research errors are differences between observed values and what is true in nature, which may result in inaccurate observations. There are two types of errors—random and systematic. Random errors occur by chance and could be caused by slight variations in the measurement instrument, the environment, the method of measurement, etc., and do not happen all the time. To minimize random errors, researchers can use replication, that is, repeating the measurements several times and then taking the average. 

Systematic error gives measurements that are consistently different from the true value in nature, possibly due to limitations in the measurement instrument or the method. 

Q5. What ethical considerations are important in experimental research? 

A5. The integrity of an experimental research study relies significantly on the adherence to ethical considerations. Readers need to be assured that the researchers have followed all appropriate rules such as those on human rights, animal welfare, safety, etc. Most of the experimental research we conduct includes people and many topics that are being researched could be sensitive to specific segments of the population and may not be ethically acceptable. Researchers need to follow specific ethical principles to ensure that the research objective and methods are transparent and are communicated clearly with the participants. These ethical principles include the following:8 

• Informed consent: Participants’ written informed consent is required to conduct the study or to publish the research results. 
• Voluntary participation: Participants should not be coerced into taking part in the study. 
• Confidentiality and anonymity: Participants’ personal data should be strictly confidential and should not be traceable back to them. 
• Deception: No aspect of the study should be withheld from the participants. 
• Accuracy in analysis and reporting: Results should be reported accurately and clearly. 

To conclude, experimental research is a type of research design that helps researchers establish the cause-and-effect relationship between variables. This type of research has several uses across industries and can help businesses make informed decisions for operational excellence. 

We hope that this article has helped you gain a better understanding about experimental research, its types, and differences from non-experimental research and will be useful in choosing the right experimental research design for your study. 

References 

1. Bhattacherjee A. Chapter 10 Experimental research. Social science research: Principles, methods, and practices. University of South Florida. Accessed December 3, 2024. https://courses.lumenlearning.com/suny-hccc-research-methods/chapter/chapter-10-experimental-research/ 
2. Experimental design: Guide, steps, examples. Dovetail. Updated April 27, 2023. Accessed December 4, 2024. https://dovetail.com/research/what-is-experimental-design/ 
3. Saha S. What is experimental research? Definition, types & examples. Entropik. Accessed December 5, 2024. https://www.entropik.io/blogs/experimental-research 
4. What is experimental research? Voxco. Accessed December 5, 2024. https://www.voxco.com/blog/what-is-experimental-research/#:~:text=Experimental%20research%20is%20a%20scientific,and%20strength%20of%20such%20relation. 
5. True experimental design: Types & how to conduct. Voxco. Accessed December 6, 2024. https://www.voxco.com/blog/true-experimental-design/ 
6. Kumar, R. Experimental method: Advantages and limitations. Accessed December 7, 2024. https://rrscollegemokama.ac.in/study-material/1572486481experimental%20method.pdf 
7. Practices of science: Scientific error. Exploring our fluid Earth. Accessed December 8, 2024. https://manoa.hawaii.edu/exploringourfluidearth/physical/world-ocean/map-distortion/practices-science-scientific-error 
8. Research design and ethics. American Psychological Association style manual. Accessed December 9, 2024. https://www.apa.org/pubs/books/supplemental/Designing-Proposing-Research-Project/research_design.pdf 

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