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Enhancing Measurement Precision, Accuracy, and Validity

Learn how to improve precision, accuracy, and validity of measurements through strategies and techniques, exploring the impact of errors and biases. Enhance your data reliability with insightful practices.

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Enhancing Measurement Precision, Accuracy, and Validity

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  1. Precision, Accuracy, And Validity Precision:-a very precise measurement is a one that has nearly the same value each time it is measured. A scale measurement is more precise than a qualitative one. The more precise a measurement the greater the statistical power. Assessing precision: usually by S.D.of repeated measurements, also the Co.V. or correlation coefficient.

  2. Precision is usually affected by random errors, there are 2 main sources of errors: • Subjective:- subject variability due to intrinsic biological variability ex.: fluctuation in mood, B.Pr., heart rate… • Objective: • 1- Observer: hand-eye coordination • 2- Instruments: due to fluctuating environmental factors such as temperature, background noise,…

  3. Strategies For enhancing precision: Through decreasing random errors, and this is done by: 1- Standardizing the measurement method 2- Training & certifying the observer 3- Refining the instruments 4- Automating the instruments 5- Repetition: repeat the measurement & use the mean

  4. Accuracy The accuracy of a variable is the degree to which it actually represents what it is intended to represent.

  5. Accuracy is affected by systematic errors (bias) of two types: 1- Subjective: Co-operation, re-call, illiteracy… 2- Objective : -observer: conscious or un-conscious -Instruments: which are not calibrated recently. .

  6. Strategies for enhancing accuracy: The same 1-4 strategies of precision and : 5- Making unobtrusive measures: design measurements that the observer is unaware of. 6- Blinding: Single, double, triple (the researcher or the manager who is reading the outcome) 7- Calibrating the instruments The discussion on how vigorously to peruse each of these strategies depends on feasibility and cost of the strategy

  7. Validity • Predictive Validity: the degree to which the measurement successfully predicts an outcome • Criterion related Validity: the degree to which the measurement agrees with other approaches for measuring the same characteristics (ex. Question about stress) • Face Validity: a subjective judgment whether a measurement makes sense intuitively, whether it seems to be a reasonable approach.

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