Skip to main content
. Author manuscript; available in PMC: 2010 Jan 1.
Published in final edited form as: Pain Med. 2008 Sep 24;10(1):133–142. doi: 10.1111/j.1526-4637.2008.00513.x

Table 2.

Factors, item loadings, item correlations and Cronbach’s alpha for the Canine Brief Pain Inventory in dogs with bone cancer.

Factor and Items Factor Loadings* Communality+ h2 Cronbach’s Alpha# Item-total Correlation**
Severity of Pain (Eigenvalue 7.09) 0.95
 Item 1: Pain at its worst 0.86 0.82 0.83
 Item 2: Pain at its least 0.85 0.80 0.84
 Item 3: Pain at its average 0.90 0.93 0.95
 Item 4: Pain right now 0.86 0.86 0.90
Impact of Pain on (Eigenvalue 1.01) 0.93
 Item 5: general activity 0.68 0.84 0.88
 Item 6: enjoyment of life 0.65 0.62 0.69
 Item 7: ability to rise to standing 0.63 0.79 0.83
 Item 8: ability to walk 0.72 0.82 0.85
 Item 9: ability to run 0.89 0.87 0.81
 Item 10: ability to climb stairs 0.85 0.78 0.71
Total Instrument 0.95
*

Factor Loadings are the correlations between the items and the factors. Loadings higher than 0.4 indicate that the item is highly correlated with the factor(67–70)

+

Communality is the proportion of each item’s variance that can be explained by the factor. If an item has a communality < .40, it may either not be related to the other items, or suggest an additional factor that needs to be explored.(67, 71)

#

Cronbach’s alpha measures the extent to which the item responses correlate highly with each other. The alpha should be .70 or higher for a set of items to be considered a scale.(30, 72, 73)

**

Item-total correlations are the correlations of the individual item with the total scale (with that item omitted). Items should correlate with the total score above 0.20 to be retained.(30, 68)