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Systematic Error vs. Random Error: What's the Difference?

Edited by Harlon Moss || By Janet White || Published on December 4, 2023
Systematic error is a consistent, repeatable error associated with faulty equipment or flawed methodology, while random error is unpredictable and varies each time a measurement is made.

Key Differences

Systematic error occurs consistently in the same direction and is often linked to a problem with the experimental setup or measurement device. Random error, however, varies unpredictably and is caused by unknown and unpredictable variations in the measurement process.
Systematic error can be identified and corrected once its source is known, making it possible to improve accuracy in measurements. In contrast, random error, due to its unpredictable nature, cannot be completely eliminated but can be reduced by repeated measurements and averaging.
The presence of systematic error skews all measurements in a specific way, which can lead to a bias in the results. Random error, on the other hand, leads to a spread of results around the true value, affecting the precision but not necessarily the accuracy.
Systematic error affects the validity of an experiment by consistently distorting the data. Random error, while impacting the reliability, does not systematically bias the outcome but rather introduces variability.
Examples of systematic error include miscalibrated instruments or consistent procedural flaws. For random error, examples include environmental fluctuations or unpredictable variations in measurement readings.

Comparison Chart


Consistent and directional
Unpredictable and varies


Faulty equipment, flawed methodology
Unknown variations, environmental factors

Impact on Results

Skews results in a specific direction
Introduces variability around true value


Identifiable and correctable
Cannot be eliminated, only reduced

Effect on Experiment

Affects accuracy and validity
Affects precision and reliability

Systematic Error and Random Error Definitions

Systematic Error

Distorts results predictably and affects accuracy.
The consistent underestimation of results was due to a systematic error.

Random Error

An error that varies unpredictably in measurements.
Fluctuations in readings were attributed to random error.

Systematic Error

An error that consistently occurs in the same direction.
The miscalibrated scale introduced a systematic error in weight measurements.

Random Error

Affects the precision but not necessarily the accuracy.
Despite random error, the average of measurements was close to the true value.

Systematic Error

A repeatable error due to faulty equipment or procedure.
Using an outdated formula led to a systematic error in the calculations.

Random Error

Introduces variability without a consistent bias.
The scatter in the data was a result of random error.

Systematic Error

Originates from a flaw in the experimental setup.
Improper alignment of the sensor was the cause of the systematic error.

Random Error

Caused by unknown or unpredictable factors.
Random error was suspected due to environmental variability.

Systematic Error

Error that can be identified and corrected.
Calibrating the thermometer eliminated the systematic error in temperature readings.

Random Error

Cannot be completely eliminated, only minimized.
Taking multiple readings helped reduce the impact of random error.


How does random error differ from systematic error?

It's unpredictable and varies with each measurement.

What is a systematic error?

An error that consistently occurs in the same direction.

Does systematic error affect accuracy?

Yes, it skews results in a specific direction.

Can systematic error be corrected?

Yes, once identified, it can be corrected.

How does systematic error impact experimental validity?

It leads to consistent bias, undermining validity.

What causes systematic error?

Faulty equipment or errors in the experimental design.

How does averaging multiple readings affect random error?

It helps reduce the impact of random error.

Can random error be eliminated?

No, but it can be minimized through repeated trials.

Is random error due to faulty equipment?

No, it's typically due to unpredictable factors.

What is an example of systematic error in a lab?

Using a miscalibrated balance consistently giving wrong weights.

Is random error the same in every experiment?

No, it varies unpredictably.

Is calibration useful for minimizing systematic error?

Yes, proper calibration can correct systematic error.

Does random error indicate a flaw in methodology?

Not necessarily, it often arises from uncontrollable factors.

Is systematic error more serious than random error?

It can be, as it directly affects accuracy and validity.

Can training reduce systematic error?

Yes, proper training can reduce errors in methodology.

Does random error affect long-term studies?

It can, especially if it introduces significant variability over time.

Can random error lead to a biased outcome?

No, it doesn't bias the outcome in a specific direction.

Does random error affect the precision of results?

Yes, it leads to a spread of results around the true value.

How does instrument precision relate to random error?

Higher precision instruments reduce the magnitude of random error.

Can systematic error be detected through repeated measurements?

Yes, its consistent nature makes it detectable.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.

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