Types of Experiment Groups

This section provides you with a glossary of common terms found within science research. Further in this guide you will find a Reliability Checklist. This checklist is a tool you can use to assess the science material you are working with for reliability. For many who are not trained in science, the terminology on that list will be foreign. The glossary below is here to help you understand the meaning and context of the vocabulary on that reliability checklist.

Experiment + Control Groups

In this section I am almost always speaking about experiments or studies which involve humans, as this is especially relevant research to embodiment fields. The people involved are often referred to as participants or subjects.

During an experiment, researchers will select a group of subjects and assign them a task. Or, the subject group might receive a treatment or critical ingredient. This sub-group is often referred to as the experiment, test, or treatment group.

Often researchers will create a second group which does not undergo the same task, treatment or critical ingredient as the test group. This group is called a control group. [1]

For example, let’s say an experiment was set up to measure brain activity of experienced dancers when they were engaged in a specific somatic standing practice. These dancers would be the test group. The ‘specific somatic standing practice’ would be the task.

If a control group were added to this experiment, those people could potentially be a different group of dancers. They might have their brain activity measured without ever doing the ‘specific somatic standing practice’ task.

Having a control group helps researchers narrow in on certain information. It helps them see more clearly what, if any, change occurs in relation to a given treatment. Also, control groups can help to reduce biases held by the researchers. [2]

Types of Controls

There are many ways to design a control group. It is important to keep in mind that researchers do not always use the same names or terminology to describe control groups. Here I include some of the more commonly found terms for control design, largely drawing form the work of Dr Daniel Simons and Dr Walter Boot. [3]

  • Active Control Similar to a test group which is assigned some task or treatment, an active control group is also assigned a task. The tasks performed by an active control group differ from those performed by the experiment group. [2]
  • No Contact or Passive Control This group does not complete any task during the experiment. They have very little to no-contact with the experimenters. [2]
  • Waitlist Control – This group is informed that they will receive the same treatment as the experiment group, at some point in the future. [2]
  • Placebo Control The procedures or tasks for this group appear identical to the test group. However, in the placebo group, the ‘critical ingredient’ of the treatment is not present. [2]
  • Single-Blind Control In this design style participants are unaware whether they are in a test or control group. [3]
  • Double-Blind Control – Participants are unaware whether they are in a test or a control group. As well, the respective researchers are unaware which participants are in which group. [3]
  • Randomized Control Trial In this design participants are randomly assigned to either a test or control group. [3]
  • Quasi Experimental Control – This is sometimes referred to as non-equivalent control groups. This is a style wherein controls are naturally formed from pre-existing groupings, or any situation wherein controls are not randomly assigned. One example of this sort of group selection could be culling participants from within a buddhist sangha for a study related to meditation. [4]

This list of design styles is not exhaustive. It is simply meant to give you a basic idea about control designs frequently found in research. It is also important to note – control designs can overlap or include multiple aspects of design.

To clarify this, recall the earlier research example of experienced dancers engaged in a ‘specific somatic standing practice’. In addition to the test group, this ‘dancers’ experiment might include:
-An active control, made of dancers who are tasked with a specific sitting meditation instead of the ‘standing practice’.
-A waitlist control may be added as well.
-Additionally, participants may be randomly assigned to each group.
-Or, researchers might use a quasi-experimental design, seeking out participants who already engage in this specific somatic standing practice.
-Another design form might shift the variable of isolation via creating a control group of people not-trained in any form of dance, but who are instructed to perform the same somatic standing practice as the test group.
Many more variations are possible. Each variation will bring forth different information.

sources

  1. What an experimental control is and why it’s so important. Science Trends. (2020, March 3). Retrieved March 31, 2020, from https://sciencetrends.com/experimental-control-important/
  2. OSF. (2013, July 2). Frequently asked questions. OSF. Retrieved March 30, 2021, from https://osf.io/kszdu/wiki/home/
  3. Literature reviews: Types of clinical study designs. GSU Library Research Guides. (n.d.). Retrieved April 30, 2020, from https://research.library.gsu.edu/c.php?g=115595&p=755213F
  4. Chiang, I.-C. A., Jhangiani, R. S., & Price, P. C. (2015, October 13). Quasi-experimental research. Research Methods in Psychology 2nd Canadian Edition. Retrieved December 31, 2020, from https://opentextbc.ca/researchmethods/chapter/quasi-experimental-research/
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