Appointments Do Not Guarantee Higher Patient Satisfaction: Departmental Heterogeneity in Outpatient Waiting Performance

Technical Summary: Departmental Heterogeneity in Outpatient Waiting Performance

Problem Statement
Appointment systems are widely implemented in healthcare to coordinate patient arrivals, reduce clustered queues, and improve service quality. While existing literature generally associates appointment systems with shorter waiting times and higher patient satisfaction, these findings often rely on hospital-level aggregates or comparisons between users and non-users. This approach may obscure critical variations in how appointment systems function across different clinical settings. The core problem addressed by this study is whether the benefits of appointments—specifically reduced actual waiting time and increased satisfaction with waiting—are consistent across different outpatient departments within the same hospital, or if they exhibit significant departmental heterogeneity. Furthermore, the study investigates whether appointment status alone is a sufficient indicator of patient experience or if factors such as actual waiting time, expected waiting time, and the alignment between the two are more informative.

Methodology
The study employed a cross-sectional observational design conducted at The Second Affiliated Hospital of Zhejiang Chinese Medical University in China. Data were collected from two distinct outpatient departments: Ophthalmology (a high-volume specialty with typically longer waits) and Gynecology (a lower-volume specialty with shorter waits).

• Participants: A total of 996 valid paired questionnaires were analyzed from patients waiting for consultation. The sample included 500 patients from Ophthalmology and 496 from Gynecology.
• Data Collection: A two-stage survey process was utilized. In Stage 1, immediately upon entering the waiting area, patients reported their expected waiting time. In Stage 2, immediately before entering the consultation room, they reported their actual waiting time (calculated from check-in/registration to call time) and rated their satisfaction with waiting on a 0–100 scale.
• Variables:
  • Independent Variable: Appointment status (Appointment vs. Walk-in).
  • Outcomes: Actual waiting time (minutes) and Satisfaction with waiting (0–100 points).
  • Covariates: Age group, sex, educational attainment, and previous visit experience.
  • Exploratory Measures: Appointment punctuality (called within or by the end of the scheduled window) and expectation fulfillment (whether actual wait exceeded expected wait).
• Statistical Analysis:
  • Waiting Time: Ordinary Least Squares (OLS) linear models with heteroskedasticity-consistent (HC3) covariance estimates were used to assess the interaction between appointment status and department, controlling for covariates.
  • Satisfaction: Fractional logit models with HC3 sandwich covariance estimates were employed. Three sequential models were fitted: (1) adjusting for demographics; (2) adding actual waiting time; (3) adding expected waiting time and interaction terms.
  • Multiple Testing: Holm's step-down procedure was used to adjust P-values for multiple comparisons.

Key Results
The study revealed significant departmental heterogeneity in the relationship between appointment status and patient experience:

1. Waiting Time Reduction:

   • Ophthalmology: Appointment patients waited significantly less than walk-in patients. After adjustment, the difference was 6.43 minutes (95% CI: −9.02 to −3.84; P<0.001).
   • Gynecology: No statistically significant difference was found. The adjusted difference was −1.53 minutes (95% CI: −3.77 to 0.72; P=0.184).
   • Interaction: The difference in waiting-time advantage between the two departments was statistically significant (4.91 minutes; P=0.009), confirming that the benefit of appointments is not uniform.

2. Satisfaction with Waiting:

   • Ophthalmology: Appointment patients reported significantly higher satisfaction than walk-in patients. In Model 1, the adjusted difference was 8.15 points (P<0.001).
   • Gynecology: No significant difference was observed between appointment and walk-in patients (difference: −0.41 points; P=0.656).
   • Drivers of Satisfaction: When actual waiting time was added to the model, the satisfaction gap in Ophthalmology narrowed but remained significant. Crucially, among appointment patients, exceeding expected waiting time was strongly associated with lower satisfaction (8.78 points lower; P<0.001). In contrast, the specific position of the expected call relative to the scheduled window (before, within, or after) was not independently associated with satisfaction once actual and expected waits were accounted for.

3. Appointment Punctuality:

   • Both departments exhibited high punctuality rates (90.1% in Ophthalmology and 95.1% in Gynecology were called by the end of their window). However, high punctuality in Gynecology did not translate into a waiting-time or satisfaction advantage over walk-in patients, indicating that punctuality and relative waiting advantage are distinct operational measures.

Key Contributions

• Departmental Heterogeneity: The study demonstrates that the operational value of an appointment system is context-dependent. An appointment system that yields shorter waits and higher satisfaction in a high-volume department (Ophthalmology) may not produce the same results in a lower-volume department (Gynecology).
• Decoupling Punctuality from Advantage: The research distinguishes between appointment punctuality (meeting a scheduled threshold) and appointment waiting advantage (waiting less than walk-in patients). A department can have high punctuality without offering a relative waiting advantage to appointment holders.
• Expectation Fulfillment: The findings highlight that for appointment patients, the critical determinant of satisfaction is whether the actual wait exceeds the expected wait, rather than the strict alignment of the call time with the scheduled window.
• Limitations of Aggregate Metrics: The study argues that hospital-level indicators or simple user/non-user comparisons may fail to capture the nuanced reality of outpatient waiting performance, potentially masking department-specific inefficiencies.

Significance and Claims
The authors conclude that appointment status alone is not a guarantee of higher patient satisfaction or shorter waiting times. The significance of the study lies in its observational evidence that the relationship between appointments and patient experience is mediated by department-specific factors, such as workload, service processes, and the balance between demand and capacity.

The paper explicitly states that these findings describe observational associations and do not establish causal effects. The authors refrain from proposing specific causal mechanisms or intervention strategies, noting that unmeasured factors (e.g., staffing levels, clinical complexity, queueing rules) may influence the results. Instead, the study suggests that hospital managers should evaluate appointment services at the departmental level, jointly monitoring appointment use, actual waiting times, expectation fulfillment, and satisfaction. The core message is that the operational value of appointments must be assessed within the specific context of each clinical setting rather than assumed to be uniform across a hospital.