How to Read Radar Charts

The LibQUAL+® survey asks participants 22 questions to assess the quality of library services using three criteria. Each of the criteria is on a scale of 1-9. The criteria are:

Perceived service level – what the user sees.
Desired service level – what the user wants.
Minimum acceptable service level – the lowest acceptable level of service.
Respondents’ minimum, desired, and perceived levels of service quality are aggregated and plotted on each axis of the radar charts. Each axis represents one of the 22 questions.

The resulting “gaps” between the three levels are shaded in blue, yellow, green, and red.

Blue and Yellow: Generally, a radar graph shaded blue and yellow indicates that users’ perceptions of service fall within the “zone of tolerance.” The distance between minimum expectations and perceptions of service quality is shaded in blue, and the distance between their desired and perceived levels of service quality is shown in yellow.

When users’ perceptions fall outside the “zone of tolerance,” the graph will include areas of red and green shading.
Red: If the distance between users’ minimum expectations and perceptions of service delivery is represented in red, that indicates a score that falls short of minimum acceptable service levels.
Green: If the distance between the desired level of service and perceptions of service delivery is represented in green, which indicates a score that exceeds the desired service level.