Evidence pointing toward invalidity of the SF-8 physical and mental scales: a fusion validity assessment

Our observations of causal incongruities question whether the SF-8 can provide valid assessments of physical and mental health. However, it would be imprudent to discontinue SF-8 use on the basis of a single study suggesting invalidity. This uncomfortable conclusion can be rechecked by re-analyzing data from any project that employed the SF-8 and recorded even one causal consequence of physical or mental health. The power of fusion validity assessment comes from connecting the recorded consequences simultaneously to both the scale and the items from which that scale is calculated.