8 junio, 2024

Experimental research: what it is, characteristics, types, examples

What is an experimental investigation?

A experimental research It is one that seeks to identify cause-effect relationships between variables, obtaining data through experimentation. To do this, it uses a control group, several experimental groups and performs the sampling randomly.

To identify cause-effect relationships, experimental researchers manipulate one or several variables in the groups undergoing experimentation. They then look at the results and compare them to the control group.

For example, a group of researchers is studying whether a drug has the power to fight pancreatic cancer. They administer the drug to an experimental group of 100 people and a placebo drug to a control group, also of 100 people.

Experimental research is a type of qualitative research widely used in various areas, such as medicine, particle physics, aeronautical technology development, power generation, neurology, psychology, among others.

A great advantage of this type of research is that it can be reproduced to verify the results. This is possible because it is carried out under rigorously controlled conditions and according to detailed and precise experimental designs.

Characteristics of experimental research

In all experimental research we can recognize these five characteristics:

1- It must have a control group and more than one experimental group. Sampling of groups is done randomly.

2- Researchers manipulate the variables. These are divided into independent and dependent. The independent is the one that has been manipulated. The dependent variables are those that are altered by the effect of the manipulation of the independent variable.

3- Its objective is to identify cause and effect relationships between the variables. This is achieved by comparing the control group with the experimental sample and observing how the independent variable modifies the dependent ones.

4- It is a type of quantitative research. It uses statistical analysis to interpret the results of the experimentation and offers specific and quantifiable conclusions.

5- It is carried out under strictly controlled conditions, so that the results are not affected by any factor beyond the manipulation exercised by the researchers. It is the way to guarantee the cause-effect relationship.

Types of experimental research

Experimental investigations are classified according to the type of experimental design they apply. These can be of three types: pre-experimental, true experimental or quasi-experimental. Let’s look at each of them a little more in detail.


It is an exploratory or preliminary investigation, which does not aspire to obtain conclusive results, but to learn more about the object of study and generate hypotheses. For this type of research, a single variable is taken into account, without manipulating it.

For example: exploring the level of literacy in primary school children diagnosed with dyslexia.

true experimental

It is experimental research proper. It starts from a hypothesis and selects one or more variables, which are manipulated in order to identify cause-effect relationships between them when comparing the control sample with the results of the experimental sample. Sampling is done randomly.

For example: determine carbon dioxide levels in the atmosphere after a forest fire, at the fire site.


It differs from the true experimental design in only one aspect: here the sampling is not carried out at random, neither that of the control group nor that of the experimental group. Groups already formed are taken.

An example might be research on the IQ of second-year high school students at a certain educational center. In this case, the group is already formed (high school students). The IQ would be the variable and the IQ test would be the experiment.

Experimental Research Techniques

In experimental research, it is very important to avoid involving extraneous variables in the experiment that could undermine the credibility of the results. To achieve this, the following techniques are applied:


It is the ideal way to control extraneous variables: eliminating them. This can be achieved by carrying out the experiment in a completely isolated and sterile environment.


If during the experiment it is not possible to keep two extraneous variables under control, the researcher must try to balance or balance the effect of the extraneous variables, so that they cancel each other out.

Constancy in the conditions

This is another technique for preventing extraneous variables from messing up experiments that have cost time and effort. It consists of keeping the influence of the foreign variable constant throughout the experimentation. In this way the influence can be measured and then discounted from the final results.

Examples of experimental research

Medication against coronavirus

A researcher wants to know if a drug helps fight coronavirus disease (COVID-19). The experimental group of 5000 people consumes the drug daily for 1 month. The control group consumes a placebo drug.

Sunlight and plant growth

A biologist wants to know if the amount of sunlight that plants receive affects how fast they grow. In an experimental group of 50 plants, apply sunlight for 6 hours a day, and in a control group of 50 plants, apply 1 hour of light.

exercise and weight loss

A researcher wants to know if exercise helps you lose weight. An experimental group of 200 people performs 5 days of exercise per week. The control group of 200 people does nothing.

Milk consumption and growth

An endocrine doctor wants to investigate whether consuming milk in children helps them grow faster. An experimental group of 1000 children aged 8-10 consume half a liter of milk per day. The control group, also 1000 children of the same age, did not consume milk. The centimeters reached in 1 year are measured.

Carbohydrate intake and cycling endurance

A scientist conducts research to determine if carbohydrate intake makes athletes more stamina. A group of 50 cyclists will consume carbohydrates the day before a 100km stage, and the control group of 50 other cyclists will consume protein. The times of one group and the other will be measured.

Anxiolytic drugs and dependence

The experimental group will consume a certain daily dose of anxiolytics; the control group will not consume them. After a certain time, a medical and psychological analysis will determine the health status of the experimental group and compare it with that of the control group, to determine if there are symptoms of dependence.

Metallic compound and conduction of electricity

The experimental group will be composed of various metals, to which an electrical discharge will be applied. The control group will consist of compounds that do not conduct electricity.

Effect of pressure and job performance

Both the control group and the experimental group will perform the same task: a list of mathematical calculations of varying complexity. The control group will be assigned a normal delivery time; that of experimentation, a time reduced by 30%. The results will be compared, taking into account the number and complexity of the solved calculations.

Side effects of taking birth control pills

A random sample of women taking birth control pills will be monitored for a period of at least two years, with regular medical examinations and a properly designed questionnaire to record any symptoms that may be considered side effects.

sleep and mood

In this investigation, the control group would sleep for eight consecutive hours, while the experimental group would rest for the same amount of time, but their sleep would be interrupted several times. A psychological interview with the members of both groups will allow the variable «mood» to be compared.

non-experimental research

Non-experimental research is all research in which variables are not manipulated. It can be quantitative or qualitative. For example, a beverage brand is planning to launch a new flavor on the market, so it uses surveys and interviews to find out which of the possible flavors would be most popular with its consumers.

Themes of interest

Scientific method.

Basic investigation.

Field research.

Applied research.

Pure research.

explanatory research.

descriptive research.

Observational study.

Documentary research.


(s/f). What is experimental research? Taken from en.surveymonkey.com.
(s/f). What is an experimental investigation? Taken from tesisymasters.com.ar.
Chavez Valdez, SM (2020). Pre-experimental and quasi-experimental designs applied to the social sciences and education. Teaching and Research in Psychology. Vol. 2, no. 2.
Rus Arias, E. (2020). Experimental research. Taken from economipedia.com.

Deja una respuesta

Tu dirección de correo electrónico no será publicada. Los campos obligatorios están marcados con *