How do you calculate Spearman-Brown reliability?

In the formula(4) r Spearman -Brown = n r 1 + ( n − 1 ) r n is the factor by which the number of items will be multiplied, and r is the reliability (internal consistency) of the questionnaire.

How do you calculate Spearman-Brown prophecy?

Spearman-Brown Formula

1. rkk = reliability of a test “k” times as long as the original test,
2. r11 = reliability of the original test(e.g. Cronbach’s Alpha),
3. k = factor by which the length of the test is changed. To find k, divide the number of items on the original test by the number of items on the new test.

How do you test for split half reliability in SPSS?

The steps for conducting split-half reliability in SPSS

1. Researchers have randomly assigned survey items into one of two equal “halves.” They have entered the data in a within-subjects fashion.
2. Click Analyze.
3. Drag the cursor over the Scale drop-down menu.
4. Click on Reliability Analysis.

How do you interpret Cronbach alpha?

Theoretically, Cronbach’s alpha results should give you a number from 0 to 1, but you can get negative numbers as well. A negative number indicates that something is wrong with your data—perhaps you forgot to reverse score some items. The general rule of thumb is that a Cronbach’s alpha of . 70 and above is good, .

What does the Spearman Brown correction do?

The Spearman-Brown prophecy formula provides a rough estimate of how much the reliability of test scores would increase or decrease if the number of observations or items in a measurement instrument were increased or decreased.

What does the Spearman-Brown correction do?

How do you calculate Cronbach alpha?

To compute Cronbach’s alpha for all four items – q1, q2, q3, q4 – use the reliability command: RELIABILITY /VARIABLES=q1 q2 q3 q4. The alpha coefficient for the four items is . 839, suggesting that the items have relatively high internal consistency.

How do you perform a split-half reliability?

One popular way to measure internal consistency is to use split-half reliability, which is a technique that involves the following steps:

1. Split a test into two halves.
2. Administer each half to the same individual.
3. Repeat for a large group of individuals.
4. Find the correlation between the scores for both halves.

What is an acceptable split-half reliability?

A general accepted rule is that α of 0.6-0.7 indicates an acceptable level of reliability, and 0.8 or greater a very good level. However, values higher than 0.95 are not necessarily good, since they might be an indication of redundance (Hulin, Netemeyer, and Cudeck, 2001).

What is Spearman’s rank-order correlation?

Spearman’s Rank-Order Correlation using SPSS Statistics Introduction The Spearman rank-order correlation coefficient (Spearman’s correlation, for short) is a nonparametric measure of the strength and direction of association that exists between two variables measured on at least an ordinal scale.

What are some alternative tests to Spearman’s correlation?

Possible alternative tests to Spearman’s correlation are Kendall’s tau-b or Goodman and Kruskal’s gamma. This “quick start” guide shows you how to carry out a Spearman’s correlation using SPSS Statistics. We show you the main procedure to carry out a Spearman’s correlation in the Procedure section.

What is the Spearman-Brown prediction formula?

The Spearman-Brown Prediction Formula, also known as the Spearman-Brown Prophecy Formula or Correction, is a method used in evaluating test reliability.

What is rank order correlation in SPSS?

Spearman’s Rank-Order Correlation using SPSS Statistics Introduction. The Spearman rank-order correlation coefficient (Spearman’s correlation, for short) is a nonparametric measure of the strength and direction of association that exists between two variables measured on at least an ordinal scale.