The validity of an ANI-based welfare index for cattle, the A-Index, was evaluated using Test Theory methods described for quality of life assessments in human medicine. Content validity was considered during the modification of the Index for Finnish beef production. In total, 43 items
evaluating locomotion abilities, lying area, social environment, management, feeding, and health of animals over six months up to slaughter were formed. Index scorings were performed on 237 farms. A most consistent partial A-Index was constructed based on qualitative item analyses. A positive
relationship was established between the full A-Index and daily carcase gain. In addition, a preliminary negative relationship was established between the partial A-Index, body fat and mortality. Based on our observations, methods used for quality of life indices in human beings would appear
suitable for animal welfare assessment. Practicability and well-defined methodology are the main advantages of Test Theory approach.