In 1959, Ragnar Frisch prompted Georg Rasch to formalise a separability theorem that continues today to serve as the basis of a wide range of theoretical and applied developments in psychological and social measurement. Previously unnoted are the influences on Rasch exerted by Frisch’s...

Invariant, additive, and separable parameters for measures of human, social, and natural capital have repeatedly proven their value and utility globally over the last 50 years. Given growing demand for comparable living capital metrics, metrological organizations should position themselves to...

Reliability coefficients indicate the proportion of total variance due to differences not attributable to error among measures separated along a quantitative continuum by a testing, survey, or assessment instrument. Person score or measure reliability is influenced by both the internal...