What is Experimental Design? A Comprehensive Guide for 2023

Experimental design is a scientific examination carried out in a controlled environment to make objective observations about the effect that an independent variable has on a dependent variable. A common type of research design to ensure conclusive and specific results, experimental design is used in most fields of study for a deeper understanding of a particular subject with clear, transparent, and unbiased data. One or more independent variables are changed and then applied to one or more dependent variables to examine their reaction. 

The efficiency of design is essential to gather quantitative data and carrying out statistical analysis during the research process. In this article, we discuss what are experimental design, its importance, and the mistakes to avoid when designing the research structure. 

Importance of Experimental Design

This type of design is an integral part of the research process. Additionally, it helps researchers devise effective decision-making procedures, structure the research for easy data analysis, and achieve the objectives of their study. Since experimental research involves complex data and procedures, it is essential to create a framework for it right at the beginning of any kind of research. Moreover, doing so helps researchers better organize the procedures, set the boundaries for the study, and enhance the credibility of the results.  

The major components of this design include: 

• A testable hypothesis statement
• An independent variable that researchers can change or manipulate
• A dependent variable that researchers can measure precisely to know the effect that the manipulation of the independent variable has on it

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Types of Experimental Research Design

Experimental research design is categorized into three types based on the methods used to collect the data for the studies.

True Experimental Research Design

True experimental research design is considered the most accurate form of research because it relies on statistical analysis to prove or disprove a hypothesis statement. In addition, it is the only type of design that establishes the cause-and-effect relationship within a specific group. In essence, this kind of experimental design involves the following factors. 

• Random variables to avoid selection biases of variables and ensure the delivery of accurate results 
• A variable that the researcher can manipulate
• Control groups, refer to research participants on whom experimental rules are not applied
• Experimental groups or groups of participants on whom the experimental rules are applied

Quasi-Experimental Research Design

A quasi-experimental design is similar to a true experimental research design, but there is a difference in the assignment of the control group. Moreover, in a true experimental research design, participants of the groups are selected randomly, which is not the case in a quasi-experimental research design. 

Therefore, this kind of research design method is used in situations where the assignment to a specific group is complex, impossible, or not required.

Pre-Experimental Research Design

Pre-experimental research design is the simplest form of such design. Here, the groups are kept under observation after identifying the cause-and-effect factors. The method is commonly used by researchers to understand whether further investigations are needed for the observed groups. 

Essentially, there are three types of pre-experimental research design:

One-Shot Case Study Design

It practices the experiment on a single group and only takes a single measurement after the experiment.

One-Group Pretest-Posttest Design

Like the previous one, this design also treats just one experimental group but takes two measures into account.

Static Group Comparison

This type compares two experimental groups. One of the groups is exposed to treatment while the other is not. The difference between the two groups is the result of the experiment.

The Experimental Design Process

There are four steps involved in the experimental design process. 

Establish Your Question and Set Variables

At this stage, a research question is established that helps to distinguish between dependent and independent variables.

State Your Hypothesis

After the question is established, you should state your hypothesis, which should be testable, and explain the objective of the research.

Design Experimental Treatments

At this stage, independent variables are manipulated to study the cause-effect relationship.

Categorize Into Treatment Groups

In the next stage, research participants are assigned to appropriate treatment groups using the right approach for the research. In essence, the right approach depends on the resources available and the objective of the research.

Advantages of Experimental Design

Experimental design empowers the researchers to enhance the efficiency of the research with a clear strategy to follow during the process. Other advantages include:

Controls Variables

Experimental design involves multiple variables, and the research design allows identifying the variables required for the study and manipulating them based on set objectives.

Analyzes the Cause-Effect Relationship

It helps the researcher to study variables in isolation and identify the cause-effect relationship.

Sets Boundaries for the Study

In experimental design, there are no study limits, and setting a boundary is crucial to produce an outcome without deviating from the core objective.

Increases the Trustworthiness of the Results

Experimental research design delivers a clear and transparent procedure of study that helps in enhancing the credibility of the results.

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6 Mistakes to Avoid When Designing Your Research

An efficient experimental research design is needed to produce accurate and credible results. However, a poor experimental design can decrease the productivity of the process and the reliability of the results. Let us discuss some of the common mistakes that can lead to poor research design.

Inadequate Study of the Literature

A comprehensive literature study compares your research work with existing studies on the subject and helps you to identify and fill the gaps in information. Additionally, an adequate study of literature is required so that you can highlight your contribution to the research field, either by value addition or by challenging existing findings or assumptions. In fact, insufficient study, therefore, will not help in achieving these objectives.

Limitations of the Research

No study is perfect, and a researcher needs to identify those limitations and incorporate them into the research design and findings. Moreover, including a statement in your manuscript about any interpreted limitations would help you to substantiate your conclusion. Not including the limitations would be construed as an error on the part of the researcher.

Insufficient or Incorrect Statistical Analysis

The accuracy of statistical evidence determines the quality of research. Therefore,  incorrect or insufficient statistical analysis would decrease the credibility of the results. So it is important to gain valid and sustainable pieces of evidence for your research.

Invalid Theoretical Framework

A comprehensive logical hypothesis is required to initiate research. So, it is important to check if your research has basic postulates and assumptions that can be tested by others. If not, your research design may be flawed, and you may need to develop a new framework.

Undefined Research Problem

You need to have clarity of the research problem. This is necessary to construct the framework to develop the research questions that address the core issue. Undefined research problems affect the research design and the conclusions.

Ethical Implications

Ethical implications are one of the most important aspects of research design, which must ensure the safety of the participants of the study. It is also important to mention what precautions have been taken to minimize any risks. In essence, failure to meet the ethical norms may question the validity of your research study and objectives.

Experimental Design Examples

Example 1

In the advertising industry, this kind of design can be used to study the impact of ads on different platforms on the sale of a product. Moreover, by comparing the outcomes of the sales, the enterprise can confirm which platform gave them more customers. In fact, companies utilize this method to analyze how different changes like prices, offers, packaging, and more affect the sales of their products.

Example 2

Experimental design can also be used to evaluate the changes occurring in plants. To study the impact of sunlight on plants, researchers collected plant samples and exposed half of them to sunlight for photosynthesis; the other half was kept away from sunlight in a dark space. Here, all other variables (nutrients, water, and soil) were constant. 

Moreover, on comparing the outcomes, researchers found that the changes occurring in the plants were due to sunlight and not because of other variables. 

Design with Emeritus

Experimental design is a significant ingredient for businesses to develop their strategies. Hence, if you are looking to pursue a career in research and its application in product development, Emeritus offers you a great way to gain in-depth insights. Explore our product design courses to know more. 

Write to us at content@emeritus.org