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Validity and Reliability - Coggle Diagram
Validity and Reliability
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Reliability - consistency, Could be completely invalid but can be consistent.
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Tools for reliability
Test-Retest Reliability: The consistency of results when the same test is administered to the same group at different points in time.
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Internal Consistency: The consistency of results across items within a test or measure. Different measures testing the same construct.
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Errors in measurement
Random error
Random error refers to the unpredictable and unavoidable fluctuations that occur in measurement processes. These errors are caused by random variations in the measurement environment, the measurement instrument, or the observer. Unlike systematic errors, random errors do not follow a consistent pattern and can cause measurements to vary in both directions around the true value.
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Lack of Bias: Random errors do not consistently skew measurements in one direction; they can lead to both overestimates and underestimates.
Reduction Through Averaging: Random errors can be reduced by increasing the number of measurements and averaging the results, as their effects tend to cancel out over many observations.
Syetematic error
Systematic error refers to consistent, repeatable errors associated with faulty equipment or flawed experiment design. These errors lead to measurements that are consistently off in the same direction from the true value, either higher or lower. Systematic errors are predictable and typically caused by issues in the measurement system, such as calibration errors, biased sampling methods, or environmental factors affecting the measurement process.
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Bias: Systematic error introduces a bias into the results, as it skews measurements in a particular direction.
Detectability and Correction: Once identified, systematic errors can often be corrected or minimized by recalibrating instruments, adjusting procedures, or using different methodologies.
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