2.3 Screening, Standardized & Non-Standardized Assessment Selection

Screening & Standardized Assessment Selection

Core Principle: Assessment selection is an exercise in diagnostic precision and clinical reasoning. A skilled occupational therapist selects tools with proven psychometric reliability and validity, applying a top-down occupational framework that evaluates real-world participation before drilling down into underlying impairment metrics.

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Clinical Screening vs. Comprehensive Evaluation

A critical distinction on the NBCOT exam is the operational boundary between a Screening and a Comprehensive Evaluation:

+-----------------------------------------------------------------------------------+
|                         SCREENING vs. COMPREHENSIVE EVALUATION                    |
|                                                                                   |
|  CLINICAL SCREENING                        COMPREHENSIVE OT EVALUATION            |
|  ------------------                        ---------------------------            |
|  * Purpose: Determine IF a full OT         * Purpose: Diagnose performance        |
|    evaluation is warranted.                  breakdowns, establish baseline,      |
|  * Scope: Brief, hands-off review of         develop individualized plan of care. |
|    records, screening tool, or brief       * Scope: Complete Occupational         |
|    observation (e.g., MoCA, TUG).            Profile, performance analysis,       |
|  * Regulatory Rule: NEVER used to            standardized testing, goal setting.  |
|    establish goals, plan treatment,        * Mandatory: Required prior to         |
|    or bill for therapy intervention.         initiating any treatment.            |
+-----------------------------------------------------------------------------------+

Roles of OTR and COTA in Screening & Evaluation:

• Occupational Therapist Registered (OTR): Legally and professionally responsible for the entire evaluation process. The OTR determines the screening scope, selects specific assessment tools, interprets all assessment data, formulates the clinical diagnosis, and writes the intervention plan.
• Certified Occupational Therapy Assistant (COTA): May contribute to the screening and evaluation process by gathering specific assessment data or administering standardized tools only after demonstrating service competency to the supervising OTR. The COTA cannot independently evaluate, interpret assessment results, or synthesize goals.

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Psychometric Properties of Standardized Assessments

Understanding assessment psychometrics is essential for selecting valid tools and defending clinical decision-making:

                    ┌──────────────────────────────────────────────┐
                    │         PSYCHOMETRIC FOUNDATIONS             │
                    └──────────────────────┬───────────────────────┘
                                           │
                ┌──────────────────────────┴──────────────────────────┐
                │                                                     │
                ▼                                                     ▼
┌────────────────────────────────────────┐  ┌────────────────────────────────────────┐
│         RELIABILITY (Consistency)      │  │           VALIDITY (Accuracy)          │
├────────────────────────────────────────┤  ├────────────────────────────────────────┤
│ * Test-Retest: Score stability over    │  │ * Construct: Measures the theoretical  │
│   time (r ≥ 0.80 desired)              │    trait/construct it claims to measure   │
│ * Inter-Rater: Consistency across two  │  │ * Content: Items represent entire      │
│   different raters (Kappa/ICC > 0.80)  │    domain of performance                  │
│ * Intra-Rater: Consistency of same     │  │ * Criterion-Concurrent: Correlates     │
│   rater over repeated trials           │    with established gold standard test    │
│ * Internal Consistency: Item harmony   │  │ * Criterion-Predictive: Predicts future│
│   (Cronbach's alpha 0.70 - 0.95)       │    real-world outcome (e.g., fall risk)   │
└────────────────────────────────────────┘  └────────────────────────────────────────┘

Norm-Referenced vs. Criterion-Referenced Tests

Diagnostic Accuracy Metrics: Sensitivity and Specificity

• Sensitivity (True Positive Rate): The ability of a screening tool to correctly identify individuals who have the condition ($\text{Sensitivity} = \frac{TP}{TP + FN}$). High sensitivity is vital when missing a pathology carries severe consequences (e.g., dysphagia or fall risk screen). SnNout: High Sensitivity, Negative result rules OUT the condition.
• Specificity (True Negative Rate): The ability of a tool to correctly identify individuals who do not have the condition ($\text{Specificity} = \frac{TN}{TN + FP}$). High specificity ensures individuals without impairment are not subjected to unnecessary interventions. SpPin: High Specificity, Positive result rules IN the condition.

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Top-Down vs. Bottom-Up vs. Contextual Assessment Frameworks

+-----------------------------------------------------------------------------------+
|                       EVALUATION PHILOSOPHY PARADIGMS                             |
|                                                                                   |
|  TOP-DOWN APPROACH (OTPF-4 Preferred)       BOTTOM-UP APPROACH (Biomedical)       |
|  ------------------------------------       -------------------------------       |
|  1. Focus on client's desired roles,        1. Focus on specific underlying       |
|     occupational performance, & context.       body structures and functions.     |
|  2. Assess actual task execution            2. Measures isolated impairments      |
|     (e.g., AMPS, PASS, Barthel, COPM).         (e.g., goniometry, MMT, visual).   |
|  3. Examine underlying client factors       3. Inactive/impaired components       |
|     ONLY as they disrupt the task.             assumed to explain disability.     |
|  * Clinical Rationale: Ensures therapy is   * Clinical Limitation: Normal ROM or  |
|    immediately relevant and functional.       strength does not equal function.   |
+-----------------------------------------------------------------------------------+

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Assessment Selection Across Clinical Settings

Assessment selection must align with patient diagnosis, clinical setting, cognitive capacity, and acute medical stability:

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Standardized Administration Ethics: Basal and Ceiling Rules

Standardized tests enforce strict administration protocols to maintain validity against normative populations:

                        BASAL AND CEILING RULES EXAMPLE

     TEST START (Item 10 based on chronological age)
          │
          ├── Item 10: Correct [1]
          ├── Item 11: Correct [1]  <─── BASAL ESTABLISHED (e.g., 3 consecutive correct)
          ├── Item 12: Correct [1]       (All prior items 1-9 automatically scored correct)
          ├── Item 13: Correct [1]
          ├── Item 14: Incorrect [0]
          ├── Item 15: Incorrect [0]
          └── Item 16: Incorrect [0] <── CEILING REACHED (e.g., 3 consecutive incorrect)
                                         (Testing terminates immediately)

Key Testing Principles:

1. Basal Rule: The designated entry-level score criteria that allows the examiner to assume all items prior to the basal would be performed successfully. If the client fails any initial basal item, the examiner tests backward in reverse order until the basal threshold is met.
2. Ceiling Rule: The stopping point representing the upper limit of the client's ability. Once the ceiling threshold is reached (e.g., 3 consecutive zero scores), testing is discontinued to prevent client fatigue, frustration, and invalid measurement.
3. Fidelity vs. Accommodations: Standard accommodations (e.g., wearing corrective eyeglasses, utilizing hearing aids) are permitted if specified in the manual. However, unstandardized modifications (e.g., rephrasing prompts, translating non-validated languages, offering extra demonstration) invalidate the standardized normative comparison; results must be documented qualitatively rather than as standard scores.

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Non-Standardized (Informal) Assessment: Purpose, Advantages & Limitations

The blueprint asks for the administration, purpose, indications, advantages, and limitations of standardized and non-standardized tools. Everything above covers the standardized half. The other half is not a lesser fallback — it is a deliberate clinical choice, and NBCOT writes items in which the standardized option is the wrong answer.

A non-standardized (informal) assessment has no fixed administration protocol and no normative comparison sample. It includes structured or unstructured clinical observation of task performance in the natural context, unstructured and semi-structured interviews with the client and caregivers, chart and record review, therapist-constructed checklists, and trial use of adaptive equipment or assistive technology.

When Non-Standardized Assessment Is the Correct Choice

• The client cannot follow a standardized protocol — severe cognitive impairment, receptive aphasia, low arousal, acute medical instability, behavioral dysregulation, or a young child who will not sit for structured testing.
• The norms do not fit the client — the client falls outside the normative sample's age, culture, language, or diagnostic group, so the standard score would be meaningless or discriminatory.
• The clinical question is contextual — "can this person make breakfast in their own kitchen, with their own equipment" is not answerable from a normed subtest score.
• Time and setting constrain testing — an acute-care therapist with a 20-minute window and a discharge decision to inform observes an actual transfer rather than administering a full battery.
• A standardized test was modified — the moment administration is altered beyond the accommodations the manual permits, the result becomes non-standardized data. Report the qualitative findings; never report standard scores or percentiles from a modified administration.

Advantages vs. Limitations

The Exam Decision Rule

Read what the stem is asking the score to do:

• Stem says establish eligibility, compare to same-age peers, document measurable progress for the payer, or defend the finding → choose the standardized tool.
• Stem says the client cannot follow directions, norms do not exist for this population, or the question concerns real-world contextual performance → choose the observation-based, non-standardized option.

Best practice is not either/or. Skilled evaluation pairs a standardized measure for the defensible, comparable baseline with non-standardized observation and interview for the contextual picture that actually drives the intervention plan.