In LibQUAL+, a context for interpreting the scores to the survey questions is created by asking the respondents to rate their attitudes about library service along three dimensions: Service Affect, Library as Place, and Information Control.
Users are asked to give three ratings for each question, on a scale from 1 to 9, with 9 being the most favorable:
1. The number that represents the “Minimum” level of service considered to be acceptable.
2. The number that represents the “Desired” level of service or the service the user personally wants or expects from superior libraries. These scores indicate what items are most important to the user.
3. The number that represents the “Perceived” level of service or the service that the user believes the library currently provides.
A Service Adequacy Gap score can be calculated by subtracting the minimum score from the perceived score on any given question for each respondent. In general, Service Adequacy is an indicator of the extent to which we are meeting the minimum expectations of our users. A negative service adequacy gap score indicates that our users’ perceived level of service quality is below their minimum expectations for service and is printed in red.
A Service Superiority Gap score can be calculated by subtracting the desired score from the perceived score on any given question for each user. A positive superiority gap score indicates that our users’ perceived level of service quality is above their desired level of service quality and is printed in green.
Both the Service Adequacy Gap score and the Service Superiority Gap score are scaled such that higher scores are more favorable. Thus, an adequacy gap score of +1.2 is better than an adequacy gap score of +1.0. A superiority gap score of -0.5 is better than a superiority gap score of -1.0.