The IST is a test battery that can be applied for personnel selection and whenever a broad assessment of intelligence is required. The battery can be administered individually or in a group setting.
The battery contains a basic module measuring Verbal, Numerical and Figural Intelligence as well as Reasoning as a total score. Each content area of intelligence is assessed through three subtests.
The inclusion of three subtests in each area means that several different types of items are used to measure each area. Thus the battery avoids the error of simply equating one particular type of item with an individual area of ability. When all nine subtests are administered, an overall score for Reasoning is computed along with separate scores for each ability area. The extended module measures Verbal, Numerical and Figural coded Knowledge as well as a total Knowledge scale. When both the basic module and the extended module are applied, it is possible to compute scores for Fluid Intelligence and for Crystallized Intelligence. Fluid Intelligence represents those parts of reasoning that are rather independent from the acculturational context, whereas the reasoning scale as it is calculated in the basic module represents reasoning as it depends on the culture. The relation between Crystallized Intelligence and the total Knowledge scale is similar: The gc factor score represents knowledge and sophistication of the culture without a substantial influence of reasoning, whereas the total Knowledge scale represents the knowledge as it occurs in combination with reasoning. The IST thus allows intellectual abilities to be assessed in a contemporary and well-differentiated manner.
This test is also available in German, Czech, Lithuanian, Bulgarian, Dutch, and Danish vesions. The I-S-T 2000 ist available in Italian. The PC version is also available in German, Danish, and Dutch.
• Internal consistencies (Cronbach’s alpha) range from .86 to .95 for the scales and factor scores with an internal consistency of .95 for the Total Reasoning score.• Internal consistencies for the subscales range from .69 to .79 (Verbal subscales), .86 to .91 (Numerical subscales) and .76 to .82 (Figural subscales). Coefficients are presented separately for males and females as well as for the total sample.
• Item-total correlations and difficulty levels are presented for each item.• Confirmatory factor analysis supports a three factor solution. The factor correlations indicate that a second order factor representing reasoning can be formed.• Evidence of validity is derived by means of multivariate analyses. • Correlations with other assessment instruments (d2 test, WAIS-R, MWT-B, CFT 20 and FRT) as well as with school performance indicate convergent and discriminant validity.
The total normative sample consists of 1894 cases from 15 to 69 years. Age specific norms are provided. The sample came from England (London and Leeds), Ireland and Wales. It comprised male and female schoolchildren, apprentices, students and professionals from various fields.
Depending on which modules are used, time can range from 77 minutes (basic module) to 140 minutes.
In use since 2010.