SYMLOG has demonstrated robust and dependable reliability in a variety of domestic and international settings, with indices of reliability ranging from moderately strong to extraordinarily high for a social-psychological measurement system.

Research has demonstrated excellent construct and content validity for SYMLOG-based questionnaires. Ongoing criterion-based studies continue to expand the range of applications where the use of SYMLOG is scientifically well justified.

When examining quantitative data the discussion of reliability and validity is founded on the understanding that an instrument produces a single "score". However, the SYMLOG-based questionnaire, used in the iea, yields three, theoretically independent scores. This makes reporting of reliability and validity more complicated than for most instruments.*

Reliability is a generic term used to describe the dependability of a measurement device or test. The essential idea is consistency; the extent to which the measurement device yields the same approximate results when used repeatedly under similar conditions.

Validity is context sensitive and has to do with how well a device measures what it purports to measure in terms of 1) construct validity (measuring psychological attributes); 2) criterion validity (establishing a statistical relationship with a particular criterion); and 3) content validity (sampling from a pool of required content). Over 1,000,000 profiles have been collected by SYMLOG Consulting Group which allows for extensive ongoing research and refinement.

*For a complete analysis of reliability and validity as it relates to SYMLOG-based instruments please see, Robert J. Koenigs, SCG, SYMLOG reliability and validity, (1999), and Jean Leslie, Center for Creative Leadership, Feedback to managers (in press).