Behavior Fit Assessment #

The Behavior Fit Assessment is a practitioner decision tool for comparing candidate behaviors across Dispositional Fit, Capability Fit, and Context Fit. Before committing to a target behavior, compare the three dimensions for a defined population and decision horizon, then test the strongest candidates in realistic conditions.

It is not a validated measurement instrument. Treat the minimum dimension as a bottleneck and prioritization heuristic; it is not a deterministic probability of behavior.

Version note: BFA v2.0 renames Identity Fit to Dispositional Fit. Identity Fit remains a legacy alternate name so older materials can be interpreted, but it is no longer the preferred label. The change prevents confusion with self-concept or identity-based habit advice and better identifies the intended construct.

Historical assessments that used Identity Fit should remain labeled BFA v1.x. Do not silently relabel or compare those scores with v2.0 scores; rescore the candidates using the v2.0 definitions and anchors when continuity matters.

The Behavioral State Model is a practitioner diagnostic model with six Personal Components: Personality, Perception, Emotions, Abilities, Social Status/Situation, and Motivations. It also includes two Context Components: the Social Environment and Physical Environment. The Behavioral State Model is a practitioner model, not a validated psychometric instrument or a universal prediction equation. BFA is informed by that model but is not a literal one-to-one condensation or reassignment of its eight components.

Intellectual Lineage #

The Behavior Fit Assessment sits within a broader lineage of models that examine multiple conditions around behavior. BJ Fogg’s Fogg Behavior Model (B=MAP) is one antecedent: it describes behavior as occurring when motivation, ability, and a prompt converge BS-0023 . COM-B is a separate, later framework organized around capability, opportunity, and motivation.

Jason Hreha’s earlier work at the Stanford Persuasive Technology Lab, including the Behavior Wizard, is part of the practical lineage that preceded the BFA. These antecedents help explain the questions the BFA asks, but they do not directly validate the BFA’s three dimensions, 1-10 ratings, minimum-dimension rule, or 6/10 starting threshold. Those elements remain practitioner heuristics that must be evaluated against observed behavior in each use context.

The Three Dimensions #

Dispositional Fit #

Question: Does this behavior fit what this population is reliably inclined to choose and sustain over the decision-relevant time horizon?

Dispositional Fit is the degree to which a candidate behavior matches the target population’s relatively enduring tendencies and preferences over the decision-relevant time horizon. It asks whether the behavior works with the population’s baseline patterns rather than depending on a durable change in personality, preference, or characteristic response. Personality traits are stable enough to matter for this kind of selection, while still allowing meaningful variation across situations. BS-0039 BS-0048

Self-concept, domain identity, and status meaning can be useful evidence about how someone interprets a behavior. They are adjacent signals, not the definition of Dispositional Fit. BFA is not asking people to adopt an aspirational identity or become “the kind of person who” performs the behavior. See Dispositional Fit, Identity, and Durable Behavior.

What it captures:

• Relatively enduring personality tendencies
• Stable or recurring preferences, interests, and values
• Characteristic priorities, chronic motives, and typical responses when they are relevant to the behavior
• Dispositional demands created by the behavior over the time horizon being evaluated

Scoring guidance:

• 8-10: Strong match with observed, recurring tendencies and preferences across relevant situations
• 6-7: Generally compatible with the population’s baseline; no major dispositional demand
• 4-5: Requires recurring self-regulation or a tendency that is uncommon in the target population
• 1-3: Depends on enduring tendencies the target population generally does not show; sustained performance would likely require continuing support or a different behavior

Example: Location check-ins may score lower for a population with strong privacy preferences and low comfort with public visibility. Photo sharing may score higher for a segment with recurring preferences for visual expression and social sharing. These are hypotheses about observed tendencies, not claims about what identity users should adopt.

Capability Fit #

Question: Can they actually perform this behavior?

Capability Fit measures whether the target population has the actual abilities and skills required to perform the behavior. It isolates what people can do from whether the external setting gives them the opportunity, tools, time, or support to do it.

What it captures:

• Skills and knowledge required
• Cognitive and physical abilities required
• Complexity relative to the population’s current competence
• Learning or practice required before successful performance

Scoring guidance:

• 8-10: Existing abilities and skills are more than sufficient
• 6-7: Most of the population can perform it with minor instruction or practice
• 4-5: Meaningful skill development or scaffolding is required
• 1-3: The behavior requires abilities or skills most of the target population does not currently have

Example: A tap-based beginner lesson may score high when the population can use a smartphone and understand the instructions. Whether people have a phone, a quiet moment, or five available minutes belongs under Context Fit rather than Capability Fit.

Context Fit #

Question: Does their environment support this behavior?

Context Fit measures whether the external social and physical environment enables or inhibits the behavior. It does not reclassify a person’s current emotions or motivations as environmental context; those remain Personal Components in the Behavioral State Model.

What it captures:

• Social environment: roles, norms, relationships, coordination, support, and sanctions
• Physical environment: place, access, time, tools, infrastructure, cues, and material constraints
• Whether the real setting creates opportunity, friction, or competing demands

Scoring guidance:

• 8-10: Environment actively supports and reinforces behavior
• 6-7: Environment is neutral; no barriers
• 4-5: Environment creates friction; requires effort to overcome
• 1-3: Environment actively works against behavior

Example: Team messaging can score high when workplace norms require rapid coordination and the tools are available inside the existing workflow. Focused mobile viewing can score lower in settings dominated by interruptions and competing demands.

How to Use the Behavior Fit Assessment #

Step 1: Define Your Population and Candidate Behaviors #

Before scoring, clearly specify:

• Who is the target population? (Be specific: demographics, psychographics, and context)
• What behaviors are you evaluating? (List 3-5 candidate behaviors)

Step 2: Score Each Behavior #

For each candidate behavior, score the target population on all three dimensions:

Step 3: Apply the Threshold Rule #

Starting threshold: 6/10 on each dimension, subject to calibration.

A score of 6 out of 10 on each Behavior Fit Assessment dimension is a starting threshold that must be calibrated by domain, population, context, stakes, and observed behavior.

• If any dimension scores below your calibrated threshold, treat the behavior as a weaker candidate or investigate the constraint before proceeding
• Use the limiting dimension to prioritize research and intervention design
• A 9/9/4 pattern makes the 4 the first question to investigate; it does not establish a deterministic outcome

Step 4: Make the Selection Decision #

If multiple behaviors clear the calibrated screen: Give priority to the behavior with the highest minimum score, then compare outcome impact, evidence quality, measurement feasibility, and realistic trial results.

If no behaviors clear the calibrated screen: Either:

1. Generate additional candidate behaviors, or
2. Design interventions to raise the limiting dimension, or
3. Reconsider whether this outcome is achievable for this population

Relationship to the Behavioral State Model #

The BFA is informed by, but is not a literal one-to-one condensation of, the Behavioral State Model. The two tools answer different questions:

• BFA: Which candidate behavior appears to fit this population and setting best?
• BSM: Which person-side or environment-side components might explain why a selected behavior is or is not occurring?

BSM v1.1 names six Personal Components: Personality, Perception, Emotions, Abilities, Social Status/Situation, and Motivations. It also names two Context Components: the Social Environment and Physical Environment. Jason Hreha’s original BSM materials used Identity as the technical umbrella for all six Personal Components. In current explanations, Personal Components is the primary label and Identity is the historical alias.

Perceptions, emotions, and active motivations may change much faster than personality or stable preferences. The full BSM keeps them on the person side and makes those mixed timescales visible; BFA does not move them into external Context Fit.

When to use the Behavior Fit Assessment:

• Strategic planning and behavior selection
• Rapid screening of candidate behaviors
• Initial prioritization before deep research

When to use the full Behavioral State Model:

• Diagnostic work when a behavior isn’t performing
• Intervention design targeting specific barriers
• Granular analysis of complex behavioral challenges

Examples (Illustrative) #

Instagram vs. Burbn #

Analysis: In this retrospective illustration, check-ins appear weaker on Dispositional Fit and Context Fit, while photo sharing appears stronger across all three dimensions. The scores organize hypotheses; they are not reconstructed measurements from Instagram’s decision process.

Quibi’s Failure #

Analysis: In this retrospective illustration, focused mobile viewing appears weakest on Context Fit. The scores identify hypotheses worth testing; they do not prove a single cause of Quibi’s outcome.

Duolingo’s Success #

Analysis: In this retrospective illustration, recurring learning preferences, low capability demands, and short sessions support the candidate behavior. The scores are explanatory examples, not measured Duolingo data.

Common Mistakes #

Scoring for Ideal Users, Not the Target Population #

Mistake: Evaluating fit based on your most engaged users rather than your median target user.

Example: Power users love your complex dashboard. Scoring based on them suggests everyone will. But most users aren’t power users, so they score lower on Capability Fit.

Fix: Score for the median user in your target population. Segment if necessary and score separately.

Ignoring Dispositional Fit #

Mistake: Focusing only on Capability and Context (“make it easy”) while ignoring whether the behavior’s recurring demands fit the population’s tendencies and preferences.

Example: Reducing friction for a behavior users do not value may still leave adoption weak.

Fix: Check Dispositional Fit alongside Capability and Context Fit. Ease alone may not resolve a mismatch with the population’s durable baseline.

Optimizing One Dimension at Another’s Expense #

Mistake: Improving one fit dimension while damaging another.

Example: Adding competitive gamification changes the social context but makes the behavior less attractive to a population with strong autonomy or low-competition preferences.

Fix: Evaluate interventions across all three dimensions. A gain that creates a loss elsewhere can weaken the overall candidate.

Key Takeaways #

1. Three dimensions, calibrated starting threshold. Begin with 6/10 for Dispositional Fit, Capability Fit, and Context Fit, then calibrate the screen by domain, population, context, stakes, and observed behavior.
2. The minimum score is a prioritization heuristic. A 9/9/3 pattern makes the 3 the first constraint to investigate and validate.

3. Dispositional Fit concerns relatively enduring tendencies and preferences. Self-concept can be evidence, but it is not the construct’s definition. BS-0039 BS-0018

4. Capability means actual abilities and skills. Context means the external setting. Keep person-side states such as emotions and motivations distinct from the social and physical environment.
5. BFA is informed by BSM, not a one-to-one condensation. Screen with BFA; diagnose with the full eight-component BSM.
6. Score for your actual population and horizon. Not ideal users or an abstract average.

See also:

• Behavior Matching: The full process for selecting and validating behaviors
• The Behavioral State Model: The complete 8-component diagnostic framework
• Four-Fit Hierarchy: Where behavior selection fits into the validation sequence