Statistics - Reliability (Reliable Measures)

Card Puncher Data Processing

About

How do we know how reliable our measure are.

Raw scores (X) are not perfect. (Classical test|True score) theory asserts that raw scores are influenced by:

A Raw score is considered to be reliable as it approaches the true score.

Method

Test Retest and Parallel are really hard to do because they are time consuming. Inter-item is the most commonly used method in the social sciences.

Test Retest

Just measure twice. It should be a strong correlation. The correlation between X1 and X2 is an estimate of reliability

It wouldn't detect the bias.

Parallel test

Just take two different instruments and seeing if those are correlated. The correlation between X1 and X2 is an estimate of reliability.

The bias must be detected.

Inter-item

Reliability in one measurement, in one time point but with two set of measurement (questions for instance) that must be correlated.

The correlation between X1 and X2 is an estimate of reliability.





Discover More
Anscombe S Quartet 3
Statistics - Assumptions underlying correlation and regression analysis (Never trust summary statistics alone)

The magnitude of a correlation depends upon many factors, including: Random and representative sampling Measurement of X and Y: Reliability of X and Y Validity of X and Y Several other assumptions:...
Covariance
Statistics - Correlation (Coefficient analysis)

Correlation is a statistical analysis used to measure and describe the relationship betweentwo variables. The Correlations coefficient is a statistic and it can range between +1 and -1 +1 is a perfect...
Anscombe Regression
Statistics - Regression

Regression is a statistical analysis used: to predict scores on an numeric outcome variable, based on scores of: one predictor variable: simple regression or multiple predictor variables: multiple...



Share this page:
Follow us:
Task Runner