The concept of reliability refers to 2 different characteristics. The degree to which a scale represents a single focused trait is termed internal consistency, while the degree to which a person's score is dependable, or repeatable from one time to another is termed stability.

The following tests were conducted on the Communication Survey to ensure the internal consistency as well as the stability of the survey:

The Split-Half Reliability test
Cronbach's coefficient alpha
The Test-retest

With regards to external validity, correlative tests were conducted on the communication survey with other similar instruments to ensure that the survey measured what it is supposed to measure. The communication survey was tested on its content validity, showing that the content of the test is representative of the characteristics that are of interest and on criterion-related validity, which refers to the test scores to make predictions about other characteristics of interest.

For traits of the communication survey, content validity was assured by developing a universe of content for each trait, and employing item selection procedures to ensure that the adjectives used in the final form were representative of the universe of content.

Respondent Feedback
Over 97% of the users of the communication survey rated the survey as being 90% accurate. Thus, further supporting the validity of the survey.

The comprehensive research report on the validity and reliability for the Drake P3 system can be found in the Drake P3 Research Monograph.