Validity, reliability, accuracy and precision


Primary source:

The validity of an experiment is increased if the experiment measurements are close to the true measurements. For example if you are measuring a bench height – making sure the length you read is representative of the height of the bench, the ruler is not skewed, no parallax error etc. It also requires that it is a fair measuring procedure i.e you are measuring the table you intend to measure. For example, in our table example if you wanted to know the height of your table, you would measure your table not one of the same model to approximate your table’s height. There are no uncontrolled variables affecting your experiment.

Reliability is increased if the experiment is repeated multiple times and you get the same result.

Accuracy refers to if you averaged all your measurements, how close would you be to the true value.

Precision is a measure of how close you measurements are.

The Difference Between Precision and Accuracy | Daniel Miessler

Secondary investigation:

Validity of evidence is increased if they have been gathered using appropriate methods  they relate to the hypothesis or problem 

The reliability is increased if the information is not biased  it has been written by a qualified person it is on a reputable site, i.e. .gov .edu  it is current (check date)  it refers to data and statistics from valid first-hand investigations

A sources accuracy is increased if it can be substantiated in multiple sources.


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