Table 6.
Advantages and disadvantages of objective and subjective measurement tools.
| Measurement | Advantage | Disadvantage |
|---|---|---|
| Objective | ||
| TDM | - Objective | - Dependent on patient's metabolism - Not quantitative - Does not exclude partial adherence - Cost - Availability |
| Pill count | - Easy to apply to all patients - Does not require training - Low cost |
- Missing data - Reliability |
| Pharmacy refill, including MPR | - No missing data - Not obtrusive |
- Accuracy - Variation in decision rules per study |
| Monitoring devices (smart containers) | - Reminders - Alert patients if cap is left off of bottle - Notifications of opening cap - Automatic download of data - Multiple drugs with one device |
- Leaving caps off of bottle results in missing data in most devices - High cost - Training - Underestimating adherence when multiple pills are taken out at once - Overestimating adherence with multiple openings and no pills have been taken out |
| Subjective | ||
| Self-report and observer-rated | - Easy - Short - Some take time into account - Some Likert-type rating scale |
- Cost - Some no specific timeframe - Some dichotomous - Validity - Memory bias - Poor insight may limit accuracy |