Experimentalgruppen

Experimentalgruppen, or the experimental group, is a term used in research design to denote the subset of participants that receives the intervention or treatment under investigation. The primary purpose of this group is to enable a causal assessment of the intervention by comparing its outcomes with those of a comparison group that does not receive the intervention. This setup aims to isolate the effect of the independent variable.

In most experiments, participants are randomly assigned to the experimental group or a control group to reduce selection bias. In some designs, particularly within-subject designs, the same participants serve as their own controls. The control group may receive a placebo, a standard treatment, or no intervention at all, depending on the study question and ethical considerations.

Outcomes are measured using predefined variables, and analyses compare groups to estimate the treatment effect. Study design choices such as randomization, blinding, sample size, and preregistration influence validity and reliability. Potential threats include placebo effects, Hawthorne effects, contamination between groups, attrition, and confounding variables. Proper controls and transparent reporting help mitigate these issues.

The concept is common across scientific disciplines, including medicine, psychology, education, and social sciences. In Swedish-language science and education texts, experimentalgruppen is paired with kontrollgruppen. Ethical considerations include informed consent, safety monitoring, and adherence to standards that prevent data fabrication or selective reporting.