The availability of the RASTI-method and the realization of a commercial instrument triggered the need of an international “round robin” assessment of the prediction accuracy for speech signals in various languages. Hence an international assessment procedure was initiated with twelve participating laboratories in 11 different countries. The results of this study were published in “Acustica” (see STI-references-2014 no. 10). It also resulted in an International standard (CEI-IEC 60268-16, 1988 rev. 1). The content of this standard was mainly based on the RASTI-procedure.
The present version describes the revised (full) STI-procedure and also the STIPA-method (see: CEI-IEC 60268-16, rev. 4, 2011). The objective STI-method together with some other subjective intelligibility measures is also standardized by standard ISO-9921 and by various national standards.
An earlier overview “pps”is given by: Standardisation_STI-2014-V1,
and a “pdf” overview is given by: Standardization_STI_2014-V1.