Definition, Examples and Types of Experimental Research Designs


Table of Contents

What is Experimental Research ?

Experimental research is a scientific methodology of understanding relationships between two or more variables. These sets consist of independent and dependent variables which are experimentally tested to deduce a correlation between such variables in terms of the nature and strength of such relation. Such assessment helps in deriving a cause and effect relationship and is even used for the purpose of hypothesis testing.

In such a mechanism , independent variables involved are adjusted to discover their impact on the dependent variables. The degree to which a change in the independent variables influences dependent variables is the basis of gauging the degree of strength. Such variations are recorded over a specific period of time to ensure that the conclusions drawn about the relationship are substantive and reliable enough to assist intelligent decision making.

Experimental research deals with quantitative data and its statistical analysis which makes the study extremely useful and accurate. It finds its usability in fields of psychology , social sciences , physical evaluation and academics and are time bound studies usually used for verification purposes.

Types of Experimental Research designs


1) Pre-experimental research design :

This is an observational research mechanism used to evaluate changes in a group or various groups of dependent variables after changing the independent variable values. This is the simplest form of experimental research used to assess the need for further inspection, if satisfactory results are not derived from the observations registered.

This can further be subdivided as :

  • One-shot Case Study Research Design: A post-test study relying only on a single set of variables for observational purposes.
  • One-group Pretest-posttest Research Design : This is a combination of pre and post tests that studies a single set of variables before and after the method of testing has been implemented.
  • Static-group Comparison: The total groups of variables gets divided into 2 sub-groups, one subjected to the testing while the other group remains as it as . Observations at the end of the testing reveal the contrast between the tested and the non-tested panel.

2) True experimental research :

This is a statistical approach to establish a cause and effect relationship within a variable set. The quantitative approach of this study makes it highly accurate. The assignment of test units and treatments takes place in a randomized manner.

Apart from this , it uses the availability of a control group along with an independent variable that can be manipulated to obtain the required results.

3) Quasi- experimental research design :

Quasi-experimental research design is a partial representation of true experimental research such that it seeks to establish a cause and effect relationship by manipulating an independent variable, the only difference being that it does not adhere to random distribution of participants into groups.

Thus , Quasi- Experimental research design is only applied to those situations where there is no relevance or possibility for random distribution.

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Some examples of Experimental Research design


Employee recruitment and screening 

The recruitment of an employee to an organization requires the employee to go through a rigorous selection procedure that filters the highly suited individuals for the job from the rest of the lot. A screening process is conducted that tests the skills , qualification , experience and knowledge of the applicants before going ahead with selecting the required number of people. The selected individuals are then recruited and trained with respect to the work to be done. Following this training , these individuals are then observed for a specific frame. At the end of this time period , employee appraisals take place which reviews the performance of the employee to identify the need for any improvement or if the employee is capable of handling extra work while maintaining the same level of performance and consistency levels.

This is a simple example of one group pretest posttest research design that assists the creation of a progressive work environment that provides the room for employees to grow along with pushing the organization towards achieving objectives in an efficient manner.

Impact of online tuitions

A group of students belonging to the same class and scoring the same grades in their first term exams are selected to try out a new e-tuition app as against their existing tuition classes. This sample of students are divided into two groups : one that switches to the online educational tuition app while the other group continues to attend their existing tuition classes. This study continues till the next examination cycle , as it observes the differences in the students ability to learn , grasp concepts and their general attitude towards the process of online learning . At the end of the study , the students belonging to both the groups give their term end examinations and the differences between the performance of the students are noted to contrast the teaching methods and effectiveness of online learning vs e-learning.

Such a study is an example of static group comparison that helps in comparing , analysing and establishing one of the alternatives as a viable choice under the current scenario.


Disadvantages of Experimental Research

  • The chances of error and bias being involved in experimental research are very high. The process of controlling independent variables to study changes in the dependent variables is highly prone to human error. Further , the results can even be skewed if the values are manipulated by the researcher.
  • It is a highly expensive, time consuming and cumbersome process to carry out a thorough experimental research procedure.
  • The observational nature of the pre-test experimental research study makes it a qualitative research mechanism that does not help in deriving substantive conclusions based on hard figures.
  • It can produce artificial results . It is important to factor in all independent variables that bring out variation in the dependent variables . Failing to do this may not reflect the true picture with reference to the strength of the relationship between the variables in consideration.
  • In certain situations, It is highly risky and can lead to ethical complications if treatment is not implemented carefully.

Methods of data collection


1) Surveys :

Surveys are the easiest and the most commonly used data collection mechanism. Surveys help in achieving the coverage of all relevant areas of interest by framing a questionnaire to be filled out by the targeted respondent. This can be done physically , however , the attractions offered by the online research software allow for advance designing , distribution, collection , reporting and analysis of the information gathered. This provides a viable alternative that offers enhanced research procedures to be conducted in a swift and efficient manner.

Care needs to be taken while designing the survey as well as selecting the limited number of respondents who will assist the surveying organizations in finding answers to their research questions to fuel intelligent decision making.

2) Observation :

This method of data collection involves keeping a check on the variables under study to monitor changes and observe behaviour. It takes a long period of observation to make significant conclusions. This method also largely relies on the observer’s judgement and so is highly subjective.

3) Simulation :

Simulation replicates real life processes and situations to understand variables under consideration. The reliability of such a method heavily depends upon the accuracy with which the simulation has been created. This method finds its applicability in fields such as operational research which seeks to break down the whole idea to study narrow concepts involved. Simulations are an effective choice where accessibility and implementation are not feasible.

4) Experiments :

Experiments are carried out in a controlled environment such as a lab where influencing factors can be controlled. This also circles around field experiments, numerical and AI studies. The usage of computerized software makes data handling and management an easy task.

Experiments assist a comprehensive overview of the variables under the scope of the study. They are statistically compatible and so deliver substantive results which are objective in nature.

Difference between experimental and non- experimental research

1) Experimental research focuses on understanding the nature of relationship between independent and dependent variables involved under a particular field of study. On the other hand , Non-experimental research is descriptive in nature and so , focuses on defining a process , situation or idea.

2) Experimental research provides the freedom to control external independent variables to decipher relationships, however , such a control mechanism is absent in Non- experimental research.

3) Experimental data does not make use of case studies and published works for establishing relationships while non-experimental research cannot be carried out using simulations.

4) Experimental research involves a scientific approach whereas such an approach is absent in non-experimental research due to the descriptive nature of the study.


 The 3 types of experimental designs are :

  • Pre- experimental research 
  • True experimental research 
  • Quasi- experimental research 

The study of the impact of different educational levels , experience and additional skills on the nature of jobs , salaries and the type of work environment is a simple example that can be used to understand experimental research.

 Experimental research is a methodology used to gauge the nature of relationship between the variables in consideration.

Experimental designs are written in terms of the hypothesis that a study tries to prove or the variables the research tries to study.

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