Handbook of Management Scales/Supply base availability

Items

 * There were a lot of qualified and capable suppliers. (0.787)
 * Many suppliers had the necessary capabilities to produce all items in the bundle. (0.915)
 * Many suppliers possessed the required capacities. (0.922)

Source

 * Schoenherr/Mabert (2008): The use of bundling in B2B online reverse auctions. Journal of Operations Management, Vol. 26, No. 1, pp. 81-95.

Comments
The central value of the Likert scale was 4. However, the mean values of the items are 4.778, 4.984, and 5.071, and thus larger than 4. It might therefore be recommended to use a more explicit wording (e.g. "a very high number of suppliers" instead of "many suppliers"). This could help to approach normal distributions.