How can I calculate Cronbach Alpha for two tests that I have administered to 165 people? One test contains 110 items and the other contains 67 items. The scoring is done on the hard copies and the scores of each subscale rather than individual items are entered for further calculations. There are 11 sub-scales in the one with 110 items, and four sub-scales in the one with 67 items. Presumably, the subscales are uni-dimensional in construct, so should I be calculating alpha for them. I mean do the results become invalid if I do not find alpha for my data. Is there any other more practical way of ensuring the internal consistency, or do the original alpha values given by the developers of the scales suffice? The task of putting scores of 165 people for 177 items is not practical. My tables show scores of each subscale (not items) for all the participants. Please help me understand what is the best way to go about it.