Analysing Data and Information

Evaluating the Method

Bias is a form of systematic error resulting from the researcher’s personal preferences or motivations.

Accuracy is the degree of precision by which the experimental results were obtained. This can be effected by both equipment and method.

Validity is a question of whether or not a method addresses the set hypothesis and aims. Valid experiments appropriately test their hypotheses and meet their aims.

Reliability considers how close repeated measurements are to one another. This can be applied to individual measurements within an experiment or entire experiments themselves.

Error covers the differences between observed/recorded and actual results. It may be systematic (a constant, defined and repetitive deviation) or random (deviating unpredictably).

Improving Investigations

Note that both accuracy and reliability are affected by error.

• Accuracy is affected by systematic error, whereby measured results may be consistently similar but deviate from the actual system.
• Reliability is affected by random error, which causes measurements of the same factor to unpredictably deviate from each other, yet these may average to reflect the actual system.