The disease-specific-TACQOL-asthma questionnaire measures health-status and appraisal of health-status. The TACQOL-asthma evaluates the personal feelings about problems in the domains, 'complaints, situations, emotions, treatment and medication'. The TACQOL-asthma can be used alone or in combination …

If the ratio m/p tends to zero, where m is the number of factors m and p the number of observable variables, then the inverse diagonal element of the inverted observable covariance matrix (σ pjj) -1 tends to the corresponding unique variance ψ jj for almost all of these (Guttman, 1956). If the smallest …