# Deviation vs. Variation — What's the Difference?

Edited by Tayyaba Rehman — By Fiza Rafique — Updated on April 2, 2024
Deviation refers to the departure from a standard or norm, like errors in measurement. Variation describes differences within a group, like genetic diversity in a species.

## Key Differences

Deviation highlights the act of diverging from a predefined path or standard, often implying a discrepancy or error, such as a deviation from a planned route. Variation, on the other hand, focuses on the range of differences observed within a group, population, or set of data, reflecting diversity, such as in the coloration of butterfly wings within a species.
While deviation is typically measured against a specific benchmark or expectation, indicating how far something strays from what is considered normal or acceptable, variation is more about recognizing and categorizing the breadth of differences that exist, without necessarily comparing them to a standard. For example, variation in test scores among students showcases a range of outcomes, whereas deviation might look at how far an individual score is from the average.
Deviation often carries a connotation of error or undesirability, especially in contexts like quality control or statistical analysis, where it's important to minimize deviations to ensure consistency and reliability. In contrast, variation is a natural and expected aspect of biological, social, and physical phenomena, providing the necessary diversity for evolution, adaptation, and personalization.
In statistical terms, deviation is quantitatively measured, such as the difference between an observed value and the mean of a dataset. Variation, while it can also be measured, is more broadly used to describe the overall dispersion or spread of a dataset, like the variance or standard deviation, which aggregates individual deviations.

## Comparison Chart

### Definition

Departure from a standard or norm
Differences within a group or set of data

### Connotation

Often implies error or undesirability
Natural diversity, without negative implication

### Measurement

Against a benchmark or standard
Range of differences, dispersion

### Examples

Errors in manufacturing, deviation from a flight path
Genetic diversity, variations in test scores

### Purpose in Analysis

Identify and correct errors
Understand diversity, guide decisions

## Compare with Definitions

#### Deviation

A departure from an established path or norm.
The deviation from the project timeline led to delays.

#### Variation

The range of differences within a group.
Genetic variation is crucial for a species' adaptability.

#### Deviation

A divergence from expected behavior.
His sudden deviation from routine worried his friends.

#### Variation

Diversity in biological traits among individuals.
Variation in feather color among the birds was noted.

#### Deviation

The difference between an observed value and the average.
The standard deviation measures the average deviation from the mean.

#### Variation

Fluctuation in data or conditions over time.
Seasonal variation affects crop yields annually.

#### Deviation

The act of straying from a principle or standard.
The deviation from their core values led to the company's decline.

#### Variation

A different version of something.
She played a variation of the original song on her guitar.

#### Deviation

An error or anomaly in a process or measurement.
Quality control aims to minimize deviation in product sizes.

#### Variation

Differences in characteristics among individuals.
The variation in students' test scores reflects diverse learning abilities.

#### Deviation

The amount by which a single measurement differs from a fixed value such as the mean
A significant deviation from the average value

#### Variation

A change or slight difference in condition, amount, or level, typically within certain limits
Regional variations in house prices
The figures showed marked variation from year to year

#### Deviation

The deflection of a ship's compass needle caused by iron in the ship.

#### Variation

A different or distinct form or version of something
Hurling is an Irish variation of hockey

#### Deviation

The act of deviating or turning aside.

#### Variation

The act, fact, or process of varying.

#### Deviation

An instance of this
"We made so many deviations up and down lanes ... that I was quite tired, and very glad, when we saw Yarmouth" (Charles Dickens).

#### Variation

The extent or degree to which something varies
A variation of ten pounds in weight.

#### Deviation

Divergence from an accepted idea, policy, or norm of behavior
"Freud, as the leader of a powerful new movement, could not bear much deviation from his own central ideas" (Joseph Epstein).

#### Variation

Something different from another of the same type
Told a variation of an old joke.

#### Deviation

An instance of this; an abnormality or departure from a norm
"Vice was a deviation from our nature" (Henry Fielding).

#### Variation

Magnetic declination.

#### Deviation

Deflection of a compass needle caused by local magnetic influence, especially on a ship.

#### Variation

(Biology) The existence within a species or other group of organisms of differences in form, function, or behavior, especially when hereditary.

#### Deviation

(Statistics) The difference, especially the absolute difference, between one number in a set of data and the mean of that set of data.

#### Variation

(Mathematics) A function that relates the values of one variable to those of other variables.

#### Deviation

The act of deviating; wandering off the correct or true path or road.

#### Variation

A form that is an altered version of a given theme, diverging from it by melodic ornamentation and by changes in harmony, rhythm, or key.

#### Deviation

A departure from the correct way of acting.

#### Variation

One of a series of forms based on a single theme.

#### Deviation

The state or result of having deviated; a transgression; an act of sin; an error; an offense.
Mankind’s deviation from divine will

#### Variation

A solo dance, especially one forming part of a larger work.

#### Deviation

A detour in a road or railway.

#### Variation

The act of varying; a partial change in the form, position, state, or qualities of a thing.

#### Deviation

(aviation) A detour to one side of the originally-planned flightpath (for instance, to avoid weather); the act of making such a detour.

#### Variation

A related but distinct thing.
When the process didn't work, we tried a variation.
All of his soups are variations on a single recipe.

#### Deviation

(contract law) The voluntary and unnecessary departure of a ship from, or delay in, the regular and usual course of the specific voyage insured, thus releasing the underwriters from their responsibility.

#### Variation

(nautical) The angular difference at the vessel between the direction of true north and magnetic north.
Magnetic declination

#### Deviation

(Absolute Deviation) The shortest distance between the center of the target and the point where a projectile hits or bursts.

#### Variation

(board games) A line of play that differs from the original.

#### Deviation

(statistics) For interval variables and ratio variables, a measure of difference between the observed value and the mean.

#### Variation

(music) A technique where material is repeated with alterations to the melody, harmony, rhythm, timbre, texture, counterpoint or orchestration; but with some invariant characteristic, e.g. a ground bass.

#### Deviation

(metrology) The signed difference between a value and its reference value.

#### Variation

(genetics) The modification of a hereditary trait.

#### Deviation

The act of deviating; a wandering from the way; variation from the common way, from an established rule, etc.; departure, as from the right course or the path of duty.

#### Variation

(astronomy) Deviation from the mean orbit of a heavenly body.

#### Deviation

The state or result of having deviated; a transgression; an act of sin; an error; an offense.

#### Variation

The act of varying; a partial change in the form, position, state, or qualities of a thing; modification; alteration; mutation; diversity; deviation; as, a variation of color in different lights; a variation in size; variation of language.
The essences of things are conceived not capable of any such variation.

#### Deviation

The voluntary and unnecessary departure of a ship from, or delay in, the regular and usual course of the specific voyage insured, thus releasing the underwriters from their responsibility.

#### Variation

Extent to which a thing varies; amount of departure from a position or state; amount or rate of change.

#### Deviation

The difference between an expected value of an observation or measurement and the actual value.

#### Variation

Change of termination of words, as in declension, conjugation, derivation, etc.

#### Deviation

A variation that deviates from the standard or norm;
The deviation from the mean

#### Variation

Repetition of a theme or melody with fanciful embellishments or modifications, in time, tune, or harmony, or sometimes change of key; the presentation of a musical thought in new and varied aspects, yet so that the essential features of the original shall still preserve their identity.

#### Deviation

The difference between an observed value and the expected value of a variable or function

#### Variation

One of the different arrangements which can be made of any number of quantities taking a certain number of them together.

#### Deviation

The error of a compass due to local magnetic disturbances

#### Variation

An instance of change; the rate or magnitude of change

Deviate behavior

#### Variation

An activity that varies from a norm or standard;
Any variation in his routine was immediately reported

#### Deviation

A turning aside (of your course or attention or concern);
A diversion from the main highway
A digression into irrelevant details
A deflection from his goal

#### Variation

A repetition of a musical theme in which it is modified or embellished

#### Variation

Something a little different from others of the same type;
An experimental version of the night fighter
An emery wheel is a modern variant of the grindstone
The boy is a younger edition of his father

#### Variation

An artifact that deviates from a norm or standard;
He patented a variation on the sandal

#### Variation

The angle (at a particular location) between magnetic north and true north

#### Variation

(astronomy) any perturbation of the mean motion or orbit of a planet or satellite (especially a perturbation of the earth's moon)

#### Variation

(biology) an organism that has characteristics resulting from chromosomal alteration

#### Variation

(ballet) a solo dance or dance figure

#### Variation

The act of changing or altering something slightly but noticeably from the norm or standard;
Who is responsible for these variations in taxation?

## Common Curiosities

#### Can deviation be positive?

Yes, deviation can be positive if it leads to unexpected improvements or innovations, though it often implies a need for correction.

#### Why is deviation important in quality control?

Deviation is crucial in quality control to identify and correct errors, ensuring products meet the desired standards.

#### How does variation contribute to evolution?

Variation provides the genetic diversity necessary for natural selection, driving evolution by enabling adaptation to changing environments.

#### How do deviation and variation relate to standard deviation?

Standard deviation is a measure of variation that quantifies the average deviation of each data point from the mean, linking both concepts.

#### Is all variation beneficial?

Not all variation is beneficial, especially if it leads to undesirable traits or outcomes, but it is necessary for adaptation and evolution.

#### Why is understanding variation important in statistics?

Understanding variation is essential in statistics to analyze data dispersion, identify patterns, and make informed decisions.

#### How can deviation impact a project?

Deviation from a project's plan can lead to delays, increased costs, or failure to meet objectives, emphasizing the need for management and correction.

#### Can cultural practices influence variation?

Yes, cultural practices can influence variation, such as through selective breeding in agriculture or social norms affecting behavior.

#### What role does deviation play in process improvement?

Deviation analysis helps identify process inefficiencies and areas for improvement, guiding strategies to enhance performance and reliability.

#### How is variation managed in manufacturing?

Variation is managed through quality control and process optimization to ensure consistency and meet specifications, minimizing unnecessary diversity.

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