Meaning & use
confounding variable
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Meaning
nouncountabletechnical
An outside factor linked to both the supposed cause and the supposed effect in a study, which can create a false impression that one causes the other.
Grammar: A countable noun: one confounding variable, several confounding variables.
Patterns
- a confounding variable in something
- a confounding variable for something
Age is a confounding variable in the study, because older people both exercise less and have higher blood pressure.
Researchers tried to control every confounding variable, from sleep to diet.
If we ignore the confounding variable of income, the link between tutoring and grades looks stronger than it is.
Word forms
| plural | confounding variables |
|---|
Common combinations
- control for a confounding variable
- The team controlled for a confounding variable by comparing similar age groups.
- identify a confounding variable
- Students must identify the confounding variable in the experiment described.
- hidden confounding variable
- A hidden confounding variable may explain the strange result.
- potential confounding variables
- The report lists potential confounding variables such as location.
- rule out a confounding variable
- They repeated the trial to rule out a confounding variable.
Synonyms and how they differ
- confounder
- Confounder is the shorter form used by statisticians and means the same thing, but it is less familiar to general readers.
- lurking variable
- A lurking variable is one nobody measured or noticed, while a confounding variable may be known and still muddy the results.
- extraneous variable
- An extraneous variable is any unwanted outside factor, but it only becomes confounding when it is linked to both cause and effect.
Opposites
Word family
- confound verb
- to confuse or mix up, so that causes cannot be told apart
- confounder noun
- a confounding variable
- confounded adjective
- puzzled, or mixed together in a way that spoils a result
- variable noun
- a factor that can change in an experiment
Commonly confused: confounding variable or independent variable?
confounding variable vs independent variable
The independent variable is the one researchers deliberately change; a confounding variable changes without being planned and spoils the comparison.
Practice
A study finds that people who carry lighters get more lung disease. Smoking is the likely ___ that explains both.
Choose one answer.
Smoking is linked to both carrying lighters and lung disease, so it is a confounding variable. An independent variable is something researchers choose to change, which does not fit here.
Make it your own
Write a sentence using “confounding variable”, then check it and compare it with the examples above.