Understanding Experimental Design in Research

Experimental design is the process of conducting research in an objective and controlled manner so that precision is assured and specific conclusions are drawn regarding a hypothesis statement. It is a quantitative procedure of conducting research in which one or more independent variables are altered and applied to one or more dependent variables to determine their influence on each other. If you need help with experimental design research, our experts establish the cause-and-effect relationship in a set of variables by testing hypotheses and theories in controlled conditions. This post is a guide to experimental design, illustrating its types, processes, principles, diagrams, real-life applications, and examples for reference.

What is Experimental Design?

In an experimental design, the researcher manipulates an independent variable in a controlled setting to observe its effect on a dependent variable. It is the systematic procedure of organizing a study to meet certain objectives. It consists of two subjects: The experimental group that undergoes the treatment and the control group that consists of independent variables that are altered to examine their effect on the dependent factors. Experimental design is usually used in quantitative studies.

Types of Experimental Design

(1). Pre-Experimental Design

The pre-experimental research design is the most basic type and lacks a control group. In these studies, the researcher has to identify alternative explanations one by one, decide which are reasonable, and then use logic, design, and measurement to assess whether each one is operating in a way that might explain any observed effect. After identifying the specific variables that have a cause-and-effect relationship, a group or groups are maintained under surveillance.

(2). True Experimental Design

The true experiment design is the most accurate form of all types as it relies on statistical hypotheses to prove or disprove the cause-and-effect relationship within the groups. It can be performed on two or more randomly assigned dependent objects under research. Randomization is important in an experimental design because it ensures the validity and reliability of results. It must have a random variable, one that can be manipulated by the researcher, a control, and an experimental group. It is further categorized into the factorial experimental design and the Solomon four-group design.

(3). Quasi-Experimental Design

"Quasi" stands for partial or half. Quasi-experimental research is similar but not the same as an actual experimental study. In the true experiment design, the objects under study are randomly assigned to every unit, unlike the quasi-experimental where the participants are not picked at random. Because the subjects in these experiments are not assigned at random, they are applied in cases where randomization is difficult or impossible. It is further categorized into time series and single-case experimental design.

Experimental Design in Research

This section highlights key areas of experimental design in research, including the principles, process, diagram, and a real-life application in healthcare.

Principles of experimental design in research

(1). Randomization

The principle of randomization involves the allocation of treatment to experimental units at random to avoid any bias in the experiment resulting from the influence of some unknown factor that may affect the experiment. In the development of analysis of variance, errors are assumed to be random and independent. In turn, the observations also become random.

(2). Replication

In the replication principle, any treatment is repeated several times to obtain a valid and more reliable estimate which is impossible to obtain with one observation only. This principle provides an efficient way of increasing the precision of an experiment. The accuracy increases with the increase in the number of observations. Replication provides more observations when the same treatment is used, so it increases precision.

(3). Local control

The local control principle involves regulating all factors except the ones under investigation. The replication is used with local control to reduce the experimental error. For example, if the experimental units are divided into different groups such that they are homogeneous within the blocks, then the variation among the blocks is eliminated and ideally, the error component will contain the variation due to the treatments only. This will, in turn, increase the efficiency.

(4). Manipulation of Variables

Manipulation of variables involves altering the independent factors in the experimental research design. This allows the researcher to establish the causal relationship between the treatment and dependent variables in the study. It determines whether the independent variable causes a significant change to the dependent factor.

The Experimental Design Process

An experimental design is the systematic plan for assigning research units to certain treatments and the analysis of the results. For an exceptional experiment, the researcher must follow these steps:

Step 1: State the research question

Formulating the research question directs the course of the study to be conducted. When stating the study inquiry, devise a relevant issue impacting the community or society and record the observations, conduct rigorous research and summarize current understandings about the topic, and state a sentence highlighting the focus of the study in the form of a question. It should be specific and measurable.

Step 2: State hypothesis

The hypothesis is a proposed explanation of the outcome of the experiment. It guides the course of the research and all experimental findings are viewed through the lens of the stated prediction. In this step, write a statement that predicts the outcome of the study and identify the independent and dependent variables that will be used in the research.

Step 3: Design the experiment

When designing the experiment, highlight specific details of the experimental procedure. In this step: 1.) Identify and list all materials to be used in the study and safety precautions 2.) Illustrate numerically the number of steps to be followed when testing the hypothesis 3.) Identify the control variables 4.) demonstrate the process of data collection and recording 5.) design a data table to record information 6.) Plan an effective strategy to summarize data. A well-designed experiment addresses the predictions stated in the hypothesis.

Step 4: Conduct the experiment

When experimenting, the researcher follows the steps outlined in the design. This step involves collecting data and filling the data table with units from the procedure, identifying any sources of statistical errors, and making notes of future research ideas in the field.

Step 5: Analyze the Data

Analyzing the data involves the application of statistical analysis methods depending on the type of data collected. After conducting the analysis, synthesize and present the data using graphs and charts while observing patterns and trends. In narrative form, clearly illustrate all analyses including calculations, and draw conclusions based on the data while reflecting on the stated hypothesis.

Step 6: Communicate Findings

The aim of communicating findings is to increase the knowledge base that future studies will be built around. State the conclusions made from the study, illustrate the rationale of the research, and explain the next steps after completion. The succeeding steps can be: changing the hypothesis, redesigning the study, coming up with research questions based on the conducted research, or proceeding to a new/related area of inquiry.

Experimental Design Diagram

The experimental design diagram illustrates the essential components of an experiment. It typically consists of:

Experimental Design in Nursing and Healthcare

The application of experimental studies is viewed as an effective method in nursing methodology procedures and for evaluating healthcare interventions. It is applied in randomized control trials where a direct comparison is made between two or more treatment groups where one serves as a control for the other. The participants are randomly allocated into different treatment groups then all groups are examined over time to observe the effect of the treatments.

Example of Experimental Design in Research

A farmer wants to know the effectiveness of a certain fertilizer on their farm. So, they choose a small sector of the plantation and expose a small number of plants to the fertilizer. They then studied the results after 3 weeks and recorded the findings. If the fertilizer had a positive impact on the test plants, then they apply it to the whole farm. This is a pre-experimental design because it lacks a control group.

Benefits of Getting Help with Experimental Design

Getting help with experimental design is a good investment and cost effective because research experts deliver accurate results hence eliminating the need to redo the research, which would be expensive.

Experimental design services offer customized solutions for complicated experimental design studies. Some projects may require specific statistical analysis processes or complex variables that one may not be familiar with.

Research experts have extensive experience in conducting experimental research and are in a better position to provide more definitive conclusions about the causal relationship between variables.

Summary

An experimental design is a systematic approach that involves manipulating an independent variable to assess its effect on a dependent variable in a controlled setting. The benefit of choosing this design over the other methodologies is that the strict rules that run the process usually ensure accurate and reliable results. Researchers who are not familiar with the technicalities of the procedure of the research design process can choose to get help with experimental design from a service like ours. So, if you are looking for someone to conduct your research, our consultants are readily available to help you out! Request a free quote now via our chat below to get started! You can also contact us for a prompt response and make inquiries any time or day as we are available 24/7.