How to Calculate the Variations in the Dimensions and the Overall Score in SERVQUAL

Jaap de Jonge
Editor, Netherlands

How to Calculate the Difference Between Perception of Service and Actual Service in SERVQUAL
In the SERVQUAL model, the difference between perception of service and actual service is captured through the gap score, which helps businesses identify areas of service quality improvement. The process to calculate this difference follows these steps:
1. UNDERSTAND SERVQUAL DIMENSIONS
The SERVQUAL model evaluates service quality across five key dimensions:

Tangibles (physical facilities, equipment, appearance of personnel)
Reliability (ability to perform the promised service dependably)
Responsiveness (willingness to help customers and provide prompt service)
Assurance (knowledge and courtesy of employees and their ability to inspire trust)
Empathy (caring, individualized attention to customers)

2. COLLECT TWO SETS OF DATA
Customers are asked to rate two aspects:

Expected service (E): What they think the ideal service should be.
Perceived service (P): Their actual experience with the service.

Both are rated on a Likert scale (e.g., 1 to 7 or 1 to 5, where higher numbers indicate better service).

3. CALCULATE THE SERVQUAL SCORE
For each of the 5 dimensions, the gap score is calculated as:
SERVQUAL Score = P − E
Where:

P (Perceived Service): Customer's actual experience
E (Expected Service): Customer's expectation

If:

Score is negative → Perception is lower than expectation (service quality gap).
Score is zero → Perception matches expectation (ideal service quality).
Score is positive → Perception exceeds expectation (exceptional service).

4. COMPUTE THE OVERALL SERVQUAL SCORE
To get an overall measure of service quality, the scores across all five dimensions are averaged.
Overall SERVQUAL Score = ∑(P−E) / Number of dimensions
5. INTERPRETATION
If:

Overall SERVQUAL score is negative → Indicates a service shortfall and needing overall improvement.
Overall SERVQUAL is zero → Suggests customer expectations are precisely met.
Overall SERVQUAL score is positive → Suggests customer expectations are exceeded.

This method helps businesses identify where service gaps exist and take corrective actions to enhance customer satisfaction.

10 Common difficulties in calculating this difference

Subjectivity of Expectations and Perceptions
- Customers have varying expectations based on past experiences, personal preferences, and cultural differences. This makes standardizing expectations difficult.
- Tip: Use segmentation to group customers based on demographics and past experiences, ensuring a more accurate understanding of expectations.
Bias in Customer Responses
- Customers may provide biased responses due to personal mood, recent experiences, or social desirability, affecting the accuracy of perceived service ratings.
- Tip: Use anonymous surveys and randomized question orders to minimize response bias and encourage honest feedback.
Difficulty in Measuring Intangible Aspects
- Service quality dimensions like empathy and assurance are subjective, making them harder to quantify compared to tangible elements.
- Tip: Include behavioral indicators (e.g., employee response time, complaint resolution rates) alongside subjective ratings.
Mismatch in Rating Scales
- Some customers may use the rating scale inconsistently, leading to unreliable data when comparing expectations and perceptions.
- Tip: Provide clear explanations and examples of each rating level to help customers use the scale consistently.
Expectation Inflation
- Over time, as service standards improve, customer expectations rise, making it harder to close the service quality gap.
- Tip: Regularly benchmark against competitors and industry standards to align service goals with evolving customer expectations.
Variance Across Customer Segments
- Different customer groups (e.g., new vs. loyal customers) may have different expectations, complicating overall service quality assessment.
- Tip: Customize SERVQUAL surveys for different customer groups to capture more relevant insights for each segment.
Operational and Industry Differences
- Applying SERVQUAL uniformly across industries can be challenging, as different services (e.g., healthcare vs. retail) have unique customer expectations.
- Tip: Modify SERVQUAL dimensions based on industry-specific needs (e.g., prioritize safety in healthcare, speed in fast food).
Time and Resource Constraints
- Conducting SERVQUAL surveys and analyzing data requires significant resources, making it challenging for smaller businesses.
- Tip: Use digital surveys and automated analysis tools to streamline data collection and reduce manual workload.
Fluctuations in Service Delivery
- Service performance can vary due to human factors, making it difficult to ensure consistency between measured perception and actual service.
- Tip: Conduct SERVQUAL assessments at different times and locations to identify patterns and ensure reliability.
Gap Between Perceived and Actual Shortcomings
- Sometimes, a negative SERVQUAL score may not reflect actual operational failures but rather mismatched customer expectations.
- Tip: Cross-check SERVQUAL results with internal performance metrics (e.g., complaint logs, service audits) to validate findings.