BSA-8™: BEHAVIORAL SNAPSHOT ADHERENCE SCALE
The Behavioral Snapshot Adherence – 8 items (BSA-8™) was developed to fill a critical gap in adherence measurement: the lack of a behaviorally anchored, time-bound instrument that captures a patient’s actual medication-taking behavior in a specific, recent timeframe. Existing scales primarily rely on present-tense perception-based items, which can introduce recall bias, optimism bias, and psychometric inconsistencies. The BSA-8™ addresses these limitations by focusing on past-week concrete behavior, providing a precise “snapshot” of adherence.
Where the BAS-8™ measures predictive stability; essentially the “video” of where a patient is heading, the BSA-8™ captures the retrospective reality, the “still photograph” of what has already occurred. Together, they form a dual-lens system that grounds adherence assessment both in predictive modeling and in lived behavioral evidence.
Methodology & Conceptual Foundation
Behavioral science demonstrates that past behavior is the best predictor of future behavior. To be scientifically valid, questions about past behavior must be specific, time-anchored, and behaviorally observable. The BSA-8™ situates all questions in the past 7 days, avoiding vague “sometimes” or “ever” phrasing that can create psychometric noise. The instrument was developed following these guiding principles:
- Distinct Domains: Each of the 8 items measures a unique domain of adherence, avoiding redundancy and maximizing internal consistency.
- Intentional vs. Unintentional Nonadherence: The BSA-8 distinguishes behaviors patients' control (intentional) from lapses due to forgetfulness or logistical barriers (unintentional). This distinction is actionable for clinicians: intentional behaviors may require motivational or therapeutic intervention, while unintentional lapses benefit from practical reminders or support.
- 1:1 Alignment with BAS-8: Each BSA item is conceptually paired with a BAS-8 item, creating a yin-yang complementarity: the BAS anticipates stability, while the BSA verifies adherence in real time.
- Past-Tense Anchoring: All items are framed in past tense, increasing recall accuracy, minimizing optimism bias, and providing a concrete behavioral record.
Survey Instructions: Taking medication as prescribed can be challenging for many reasons. This questionnaire captures a behavioral “snapshot” of how you manage your medications so your healthcare team can provide better support. All questions refer to your experiences in the past 7 days. Please answer honestly. There are no right or wrong answers.
1. Missed Doses
In the past week, have you missed taking any of your prescribed medication?
☐ No ☐ Yes, once ☐ Yes, more than once
2. Dose Modification (Self-Directed)
Have you changed how much of your medication you take, other than what your doctor instructed?
☐ No ☐ Yes, once ☐ Yes, more than once
3. Timing Deviation
Have you taken your medication at a time noticeably different from your usual or prescribed schedule?
☐ No ☐ Yes, once ☐ Yes, more than once
4. Full-Day Skip
Have you gone a full day without taking a medication that you were prescribed?
☐ No ☐ Yes, once ☐ Yes, more than once
5. Symptom-Driven Change
Have you skipped or changed doses because you felt better or worse (your symptoms or side effects)?
☐ No ☐ Yes, once ☐ Yes, more than once
6. Late / Remembered After Window
Have you only remembered to take a dose after the scheduled time, so it was late or effectively missed?
☐ No ☐ Yes, once ☐ Yes, more than once
7. Supply / Access Problem
Were there times you did not have your medication available (e.g., ran out, pharmacy delay, lost medication) when you needed it?
☐ No ☐ Yes, once ☐ Yes, more than once
8. Perceived Consistency
Has your overall medication-taking felt inconsistent or irregular compared with how you were instructed to take it?
☐ No ☐ Yes, once ☐ Yes, more than once
Scoring method:
- No = 1 Yes, once = 0.5 Yes, more than once = 0
- Raw Score: Sum of all 8 items → range 0–8
- Normalized Score (BSA_norm): Raw ÷ 8 → 0–1 (higher = better adherence)
- Intentional Non-Adherence (INA) Items:
- Q2 (Dose modification)
- Q5 (Symptom-driven change)
- Q2 (Dose modification)
Behavioral Descriptors (BSA_norm)
BSA_norm Raw Score Descriptor Interpretation
0.00–0.25 0–2 Highly Prone; Adherence very limited immediate attention recommended
0.26–0.50 2.5–4 Unstable; Multiple lapses inconsistent behavior
0.51–0.75 4.5–6 Moderately Steady; Mostly adherent occasional lapses
0.76–1.00 6.5–8 Reliable; Strong adherence few or no lapses
The BSA-8™ represents a novel approach to adherence measurement. It is not a replication of existing scales but instead captures real-time adherence, providing a concrete behavioral snapshot that complements the predictive insights of the BAS-8™ and enables calculation of the Behavioral Fragility Score (BFS™). Its eight distinct domains, unified response structure, and past-tense framing support strong psychometric integrity, providing us with a high internal consistency, accurate recall, and construct validity. By distinguishing between intentional and unintentional lapses, the instrument provides actionable insights for clinicians, allowing interventions to be tailored to the specific type of nonadherence observed. The BSA-8 can function as a standalone measure of snapshot adherence or be paired with the BAS-8 for a dual assessment that combines predictive modeling with retrospective behavioral verification.
BAS-8 = video of where the patient is going
BSA-8 = snapshot of where the patient has been
Together → BFS = geometric, actionable metric of behavioral fragility.
Intellectual Property
The BSA-8™ is the intellectual property of Philip Morisky and is exclusively distributed through Adherence Cartography. Unauthorized use, reproduction, or distribution is strictly prohibited.
Exploratory and Hypothesis Generating
Disclaimer on Use of the BSA-8 Instrument
The BSA-8 (Behavioral Snapshot Adherence-8) is an exploratory, hypothesis-generating research instrument. It is currently not a validated clinical tool and should not be used as the sole basis for diagnosis, treatment decisions, or patient care planning.
Preliminary findings have provided favorable insights into its potential utility, but further validation studies are required to establish its reliability, validity, and clinical applicability. Any use of the BSA-8 at this stage should be considered investigational and for research purposes only.