Reliability
With each item in Saville Consulting Wave ® Professional Styles designed to measure a unique work variable, the challenge was to develop a questionnaire with high reliability (precision) and breadth of content built into each scale. To this end, we primarily looked for strong alternate form and test-retest reliabilities. Internal Consistency estimates are designed to be around the 0.60 to 0.80 level to avoid the problem of repetitive item content, which has been identified as leading to 'bloated specifics' in other questionnaires.
Alternate Form Reliability
The 36 dimensions of Saville Consulting Wave Professional Styles have alternate form reliabilities with a mean of 0.86 for the combined score (ipsative and normative). The minimum alternate form is 0.78 and maximum is 0.93 (N=1153).
Construct Separation
The dimensions also show clear separation from each other with every single dimension having the highest correlation with its respective scale in the other questionnaire. As an example, the Inventive dimension in the Invited Access form correlates most strongly with Inventive in the Supervised Access form, not with Abstract nor any other scale. In fact, the highest non-matched correlation is 0.60 between Reliable and Organised with their respective alternate form reliabilities being 0.91 and 0.88 (N=1153). The average intercorrelation of the normative questionnaires is only 0.26 and on the combined ipsative and normative scores the average intercorrelation of the 36 dimensions is 0.06.
Internal Consistency
The internal consistency reliabilities at standardisation have a mean of 0.76 for the 36 dimensions, a maximum of 0.87 and a minimum of 0.58 which indicates variation in breadth of the scales as predicted (N=1153).
Test-Retest
The Test-Retest study for the normative (Invited Access) form had a retest period of one month (N=112). The mean reliability is 0.79, the minimum 0.71 and maximum 0.91.
In essence, the reliabilities provide strong support that the Professional Styles dimensions have breadth, reliability, stability and construct separation.
Technical Information:
The Development of the Professional Styles Questionnaires