Chapter 4: Results
4.4. Segmentation Analysis Results
The Consistent Aikaike Information Criterion (CAIC) values were compared between latent class solutions with two to five groups. The CAIC was lower for the three-class solution (5698.589) than for the solutions with two (5706.163), four (5741.502), and five solutions (5806.839). All of these CAIC values were lower than that of the CL analysis (6362.10), suggesting that respondent preferences for community pharmacy attributes were indeed heterogeneous. The three-class solution, selected based on its CAIC value, converged after 39 iterations. Furthermore, the average maximum membership probability of the three-class solution was 0.9445, similar to that of the two class (0.9460), and higher than that of the four (0.8092) and five (0.7596) class solutions.
The utility values for each of the three identified classes are presented in Table 40.
Based on the revealed preferences of the respondents in each class, the three classes were termed the “Quality Class,” the “Relationship Class,” and the “Convenience Class.” The probability of respondents belonging to the Quality Class was highest (67.6%), followed by the Relationship Class (28.3%), and the Convenience Class (4.2%). The attribute
importance values (AIV)and relative importance of each attribute within each class are presented in Table 41 and Figures 4-5.
The Quality Class was defined primarily by strong expressed preferences for the DDI (utility: 129.9, AIV: 45.5) and the overall (mean utility: 95.0, mean AIV: 33.3) quality
measures. Differences in these two attributes combined could therefore account for nearly 80% of the difference in the utility of two pharmacy alternatives. The mean AIV of hours of operation, the third most strongly preferred attribute among members of the Quality Class), was only 7.9. In the Relationship Class, the quality measures were still the most strongly
preferred attributes, with AIVs of 24.7 for overall quality and 22.6 for DDI-specific quality.
Notably, although these quality attributes were the most important attributes relative to the other attributes, they accounted for only 48% of the difference in the utility of two pharmacy alternatives, compared to the 78% seen in the Quality Class. The AIVs for
friendliness/courtesy, communication, and pharmacist effort to get to know their patients (10.8, 9.0, and 11.5, respectively) were two to three times as high as those seen in the Convenience and Quality Classes. Finally, the smallest class, the convenience class, was distinct in its high utility ascribed to the pharmacy hours of operation, for which the AIV exceeded 50% (50.3). In that class, the quality metrics accounted for only a third of utility differences (33.7).
Significant differences in utility values were seen between at least two of the groups for all six attributes. The utilities of pharmacist effort to get to know their patients and friendliness/courtesy were significantly higher in the Relationship Class than the other two segments. The Quality Class significantly differed from the other two class in having a lower utility associated with pharmacist communication and higher utilities ascribed to five star ratings on either quality metric. Finally, the differences in the utility values for the most extended pharmacy hours were significant in the pairwise comparisons between the Convenience Class and the other two classes.
Though the four-class solution was not selected due to its higher CAIC and lower maximum membership probability compared to the three-class solution, the difference between the solutions is of interest. The four-class solution resulted in similar probabilities of membership in a Relationship Class (26.4%), Service Class (3.9%), or Quality-Focused Class (69.7%); the difference between the three and four group solutions was that the
Quality Class seen in the three-class solution was separated in the four-class solution into a Drug-Drug Interaction (DDI) -Specific Quality Class (37.0%) and an Overall Quality Class (32.7%). In the Drug-Drug Interaction (DDI) -Specific Quality Class, the attribute
importance value for the DDI quality measure was much higher (53.9) than that for the Overall quality measure (16.0). The strength of these preferences was reversed (26.7 vs.
51.0) in the Overall Quality Class. While this was a weaker class solution than that with three classes, it still suggests that underlying preference heterogeneity may exist within the Quality Class.
Among the demographic and health characteristics gathered, only knowing one’s pharmacist’s name was significantly associated with class membership (Table 42), with those assigned to the Relationship Class were more likely to know their pharmacist’s name (42.9) than those in the Convenience (29.0) or Quality (32.67) Classes (p = 0.026). The ability to detect additional, significant demographic differences between segments was likely limited by the small size of the Convenience Class. Though not significant, members of the Relationship Class tended to be more urban (31.58% vs. 25.8% and 22.0% in the Convenience and Quality Classes, respectively) (p = 0.051) and less confident in their ability to manage their health conditions (prevalence of low health confidence: 20% vs.
12.9% and 13.4%) (p = 0.074) than those in other segments. Additionally, women comprised 59.0% of those in the Quality Class but only 48.4% and 49.8% in the Convenience and Relationship Classes, respectively (p = 0.054).
Table 43. Main Latent Class Analysis Results, Utilities, by Segment
Rescaled Utilities (Standard Error)
Segment 1 Segment 2 Segment 3
Attribute Levels Relationship Class Convenience Class Quality Class
Hours of Operation
8am-6pm Weekdays; 10am-3pm
Saturday; Closed Sunday -47.75 (10.68) -206.85 (40.99) -15.65 (4.15) 9am-9pm Weekdays;
9am-7pm Saturday;
10am-6pm Sunday 43.25 (10.69) 34.79 (11.63) -2.42 (4.31)
8am-10pm 7 days/week 4.50 (10.74) 172.06 (36.14) 18.06 (4.15)
Friendliness/Courtesy Sometimes -39.27(6.58) 0.40 (8.07) -15.18 (2.49)
Always 39.27 (6.58) -0.40 (8.07) 15.18 (2.49)
Communication Sometimes -35.85 (6.56) -11.60 (7.34) -11.09 (2.70)
Always 35.85 (6.56) 11.60 (7.34) 11.09 (2.70)
Pharmacist Knows Me No -49.14 (6.57) -13.71 (6.91) -11.63 (2.53)
Yes 49.14 (6.57) 13.71 (6.91) 11.63 (2.53)
Overall Quality -101.36 (14.48) -54.50 (24.21) -113.00 (5.83)
20.37 (10.74) -14.70 (13.30) 17.37 (4.80)
80.99 (14.53) 69.20 (28.82) 95.63 (4.69)
DDI Quality -41.69 (14.34) -19.04 (16.05) -150.93 (5.13)
5.24 (11.04) -7.90 (12.07) 20.00 (4.81)
36.44 (14.14) 26.94 (16.84) 130.93 (5.13)
0 10 20 30 40 50 60 70
Relationship Class Convenience Class Quality Class
Table 44. Latent Class Analysis Results, Attribute Importance Values, by Segment
Figure 4. Latent Class Analysis Results, Attribute Importance Scores, by Segment
Segment 1 Segment 2 Segment 3
Relationship Class Convenience Class Quality Class
Attribute Rank Mean Rank Mean Rank Mean
Hours of Operation 2 15.17 1 63.15 3 5.62
Friendliness/Courtesy 4 13.09 6 0.13 4 5.06
Communication 6 11.95 5 3.87 6 3.70
Pharmacist Knows Me 3 16.38 4 4.57 5 3.88
Overall Quality 1 30.39 2 20.62 2 34.77
DDI Quality 5 13.02 3 7.66 1 46.98
Figure 5. Latent Class Analysis Results, Attribute Importance Scores, by Segment
15.17
63.2
5.62 13.1
0.1
5.1 12.0
3.9
3.7 16.4
4.6
3.9 30.4
20.6
34.8 13.0
7.7
47.0
R E L A T I O N S H I P C L A S S C O N V E N I E N C E C L A S S Q U A L I T Y C L A S S Hours of Operation Friendliness/Courtesy Communication
Pharmacist Knows Me Overall Quality DDI Quality
Table 45. Sociodemographic and Health Characteristics, by Segment Separated/Divorced/Widowed 35 (16.8) 2 (6.5) 72 (14.6)
Table 45. Sociodemographic and Health Characteristics, by Segment, continued Number (%), by Segment Relationship
Class Convenience
Class Quality Class US Census Region of Residence
Northeast 66 (31.7) 7 (22.6) 144 (29.0) Number of Chronic Medications, Care
Recipients 2.2 (3.5) 1.7 (2.9) 2.0 (3.6)
I Know My Pharmacist’s Name
Yesa 90 (42.9) 9 (29.0) 164 (32.8)
Health Confidence
Mean (SD) 8.3 (2.3) 8.8 (2.2) 8.6 (1.9)
High (≥7) 168 (80.0) 27 (87.1) 433 (86.6)