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Experiment Variables

When conducting an experiment, a researcher seeks to determine the extent to which one
variable affects another one. The variable that the researcher controls or manipulates in the
course of the experiment is the independent variable (Ingham-Broomfield, 2015). The variable
that changes when the independent variable is adjusted or manipulated is the dependent variable
(Ingham-Broomfield, 2015). It is the dependent variable that the researcher studies or measures.
In ideal conditions, a change in the dependent variable should solely be a result of change
in the independent variable. However, this is often not the case because dependent variable can
change because of other variables other than independent variables. These other variables are
extraneous variables (Ingham-Bloomfield, 2015).
Extraneous variables are factors in a study which, when left unaccounted for, may have a
negative effect on the data that the researcher collects (Ingham-Broomfield, 2015). For instance,
extraneous variables may prevent a researcher from establishing causation relationship between
the independent and dependent variables. Due to the negative effects that extraneous variables
have on study findings, researchers strive to reduce or completely eliminate their effects on their
research. There are multiple ways in which they can achieve this goal of minimizing the effect of
extraneous variables on their data.
One method is use of random sampling. This method is based on the assumption that all
groups in the experiment have extraneous factors. This method does not actually eliminate
extraneous variables in an experiment; it just makes extraneous factors equal in all of the

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experiment’s groups. The effect of extraneous variables is, therefore, significantly reduced. This
method works well when the researcher is using a large sample size (Holloway & Gallin, 2016).
A second method reducing the effects of extraneous variables is through use of
experimental designs. This method deals with the manner in which the research is designed.
Even though it does not apply in all experiments, it has the potential of completely eliminating
the extraneous variables (Holloway & Gallin, 2016).

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References

Holloway, I., & Galvin, K. (2016). Qualitative research in nursing and healthcare. John Wiley
& Sons.
Ingham-Broomfield, R. (2015). A nurses’ guide to qualitative research. Australian Journal of
Advanced Nursing, The, 32(3), 34.