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What if my Cronbach alpha is negative?
A negative Cronbach’s alpha indicates inconsistent coding (see assumptions) or a mixture of items measuring different dimensions, leading to negative inter-item correlations. A negative correlation indicates the need to recode the item in the opposite direction.
Can you use Cronbach’s alpha for dichotomous variables?
Kuder-Richardson’s coefficient (KR20) is a special case for Cronbach’s alpha when items are dichotomous. Cronbach’s alpha is a generalization of the KR20 formula. When using dichotomous data, Pearson’s r is equivalent to the Phi coefficient.
Can value of alpha be negative?
Essentially, alpha reflects the degree to which a stock’s returns meet or exceed the returns generated by the market. A stock with an alpha of zero performs in line with the market. Conversely, a negative alpha indicates the security fails to generate returns at the same rate as the broader sector.
What is a good Cronbach Alpha value?
The general rule of thumb is that a Cronbach’s alpha of . 70 and above is good, . 80 and above is better, and . 90 and above is best.
What does a negative Cronbach’s Alpha mean?
A negative Cronbach’s alpha indicates inconsistent coding (see assumptions) or a mixture of items measuring different dimensions, leading to negative inter-item correlations. A negative correlation indicates the need to recode the item in the opposite direction.
What is the reliability coefficient of Cronbach?
The alpha coefficient for the four items is.839, suggesting that the items have relatively high internal consistency. (Note that a reliability coefficient of.70 or higher is considered “acceptable” in most social science research situations.) Hand calculation of Cronbach’s Alpha
When to use consistent scales for Cronbach’s Alpha?
My personal observation has been that when someone calculatures Alpha for a mixture of scales like Dichotomous, policy-chotomous, likert etc, then probability of alpha being negative or low is higher. So the conclusion, from my observation, may be personal or biased, is that the use consistent scales be used when calculating Cronbach’s Alpha.
Is the Cronbach Alpha a measure of dimensionality?
Cronbach’s alpha is not a measure of dimensionality, nor a test of unidimensionality. In fact, it’s possible to produce a high α coefficient for scales of similar length and variance, even if there are multiple underlying dimensions. To check for dimensionality, you’ll perhaps want to conduct an exploratory factor analysis.