Psychological Assessment
Intelligence, Personality & Neuropsychological Testing
In This Section
1. Psychometric Foundations
Basic Concepts
Psychometrics is the science of psychological measurement. It involves developing and evaluating tests to ensure they measure what they claim to measure accurately and consistently.
Test Characteristics
- Standardization: Uniform procedures for administration and scoring
- Norms: Comparison group scores for interpretation
- Objectivity: Scoring not influenced by examiner bias
Types of Scores
- Raw Score: Actual number of correct responses
- Percentile: % of norm group scoring below
- Standard Scores: Z-scores, T-scores, deviation IQ
Normal Distribution
Bell Curve Properties
- 68.26% within ±1 SD
- 95.44% within ±2 SD
- 99.74% within ±3 SD
Z-Score
Mean = 0, SD = 1
T-Score
Mean = 50, SD = 10
IQ Score
Mean = 100, SD = 15
2. Reliability
Definition
Reliability refers to the consistency or stability of test scores. A reliable test produces similar results under consistent conditions.
Types of Reliability
Test-Retest Reliability
Same test administered twice to same group; correlation of scores.
- • Measures stability over time
- • Problem: Practice effects, memory
- • Interval affects correlation
Parallel Forms (Alternate Forms)
Two equivalent versions administered; correlation between forms.
- • Controls for practice effects
- • Difficult to create truly parallel forms
- • Used when retesting is needed
Internal Consistency
Extent to which items measure the same construct.
Split-Half
Correlate halves; use Spearman-Brown correction
Cronbach's Alpha (α)
Average of all split-half correlations; ≥.70 acceptable
KR-20
Kuder-Richardson; for dichotomous items
KR-21
Simplified KR-20; assumes equal difficulty
Inter-Rater (Inter-Scorer) Reliability
Agreement between two or more scorers. Important for subjective tests (essays, projectives). Cohen's Kappa corrects for chance agreement.
Standard Error of Measurement (SEM)
Estimates how much error is in a score. Lower SEM = more precise measurement.
SEM = SD × √(1 - reliability)
Confidence intervals use SEM: Score ± (1.96 × SEM) for 95% CI
3. Validity
Definition
Validity is the degree to which a test measures what it claims to measure. A test can be reliable without being valid, but cannot be valid without being reliable.
Types of Validity
Content Validity
Do test items adequately sample the domain being measured?
- • Expert judgment of item representativeness
- • Table of specifications (test blueprint)
- • Important for achievement tests
Face Validity
Does the test appear to measure what it claims? Not a true validity type but affects test-taker motivation and acceptance.
Criterion-Related Validity
Correlation between test scores and an external criterion.
Concurrent Validity
Test and criterion measured at same time. "Does it correlate with current behavior?"
Predictive Validity
Test predicts future performance. "Does it predict future behavior?"
Construct Validity
Does the test measure the theoretical construct it's designed to measure?
Convergent
High correlation with similar measures
Discriminant (Divergent)
Low correlation with different constructs
4. Intelligence Tests
Wechsler Scales
Most widely used individually administered intelligence tests. Developed by David Wechsler.
| Scale | Age Range | Current Version |
|---|---|---|
| WAIS | 16-90 years | WAIS-IV |
| WISC | 6-16 years | WISC-V |
| WPPSI | 2.5-7 years | WPPSI-IV |
WAIS-IV Index Scores
Verbal Comprehension (VCI)
Similarities, Vocabulary, Information
Perceptual Reasoning (PRI)
Block Design, Matrix Reasoning, Visual Puzzles
Working Memory (WMI)
Digit Span, Arithmetic
Processing Speed (PSI)
Symbol Search, Coding
Stanford-Binet Intelligence Scale
- Age range: 2-85+ years
- Current version: SB5
- 5 Factors: Fluid Reasoning, Knowledge, Quantitative Reasoning, Visual-Spatial Processing, Working Memory
- Scoring: Mean = 100, SD = 15
IQ Classification
| IQ Range | Classification | Percentile |
|---|---|---|
| 130+ | Very Superior | 98+ |
| 120-129 | Superior | 91-97 |
| 110-119 | High Average | 75-90 |
| 90-109 | Average | 25-74 |
| 80-89 | Low Average | 9-24 |
| 70-79 | Borderline | 2-8 |
| <70 | Intellectual Disability | <2 |
5. Objective Personality Tests
MMPI-2 / MMPI-2-RF
Minnesota Multiphasic Personality Inventory. Most widely used clinical personality test. 567 true/false items (MMPI-2) or 338 items (RF).
Validity Scales
Clinical Scales
Scores are T-scores (M=50, SD=10). T≥65 considered clinically significant.
Other Objective Tests
16PF (Cattell)
- • 16 primary personality factors
- • Based on factor analysis
- • Normal personality assessment
- • 185 items
NEO-PI-R (Costa & McCrae)
- • Big Five model (OCEAN)
- • Openness, Conscientiousness
- • Extraversion, Agreeableness
- • Neuroticism
MBTI
- • Based on Jung's types
- • 16 personality types
- • E/I, S/N, T/F, J/P
- • Popular but limited validity
Beck Inventories
- • BDI-II: Depression (21 items)
- • BAI: Anxiety (21 items)
- • BSI: Suicidal Ideation
- • BHS: Hopelessness
6. Projective Tests
Rorschach Inkblot Test
10 inkblot cards. Client describes what they see; responses reveal personality dynamics.
Scoring Systems
- Exner's Comprehensive System: Standardized scoring
- R-PAS: Current evidence-based system
Scoring Categories
- Location: W (whole), D (detail), Dd (unusual)
- Determinants: Form, Color, Movement, Shading
- Content: Human, Animal, Object, etc.
- Form Quality: Accuracy of perception
Thematic Apperception Test (TAT)
Developed by Henry Murray. 31 cards with ambiguous pictures. Client creates stories revealing needs, motives, conflicts.
- • Typically 8-12 cards administered
- • Stories analyzed for themes, hero, needs, press
- • Based on Murray's Need-Press theory
- • Children's version: CAT (Children's Apperception Test)
Drawing Tests
DAP (Draw-A-Person)
- • Draw a person; then opposite sex
- • Reveals body image, self-concept
- • Goodenough-Harris scoring for IQ estimate
HTP (House-Tree-Person)
- • Draw house, tree, person
- • House: home/family relationships
- • Tree: unconscious self-concept
- • Person: conscious self-image
Sentence Completion Tests
Client completes sentence stems (e.g., "I wish...," "My mother..."). Semi-projective; reveals attitudes, conflicts, relationships. Examples: Rotter Incomplete Sentences Blank, Forer Sentence Completion.
7. Neuropsychological Tests
Common Neuropsychological Tests
Bender Visual-Motor Gestalt Test
- • 9 geometric designs to copy
- • Assesses visual-motor integration
- • Screens for brain damage, developmental delay
- • Koppitz scoring for children
Trail Making Test (TMT)
- Part A: Connect numbers 1-25 in order (processing speed)
- Part B: Alternate numbers and letters (cognitive flexibility)
- • Sensitive to frontal lobe damage
- • Timed administration
Wisconsin Card Sorting Test (WCST)
- • Measures executive function, set-shifting
- • Sort cards by color, form, or number
- • Rule changes without warning
- • Perseverative errors indicate frontal dysfunction
Stroop Color-Word Test
- • Tests selective attention, inhibition
- • Read color words vs. name ink colors
- • Stroop effect: interference when word and color conflict
- • Sensitive to frontal lobe function
Rey Complex Figure Test
- • Copy complex figure; then draw from memory
- • Assesses visual memory, organization
- • Immediate and delayed recall
Test Batteries
Halstead-Reitan Battery
- • Comprehensive neuropsych battery
- • Impairment Index
- • Lateralization indices
- • Takes 6-8 hours
Luria-Nebraska Battery
- • Based on Luria's theory
- • 11 clinical scales
- • Shorter than Halstead-Reitan
- • Good localization
8. Ethical Considerations
Testing Ethics
- •Informed Consent: Explain purpose, procedures, confidentiality limits
- •Competence: Only administer tests you're trained to use
- •Test Security: Protect test materials from public access
- •Cultural Fairness: Consider cultural bias; use appropriate norms
- •Feedback: Provide understandable results to clients
- •Record Keeping: Maintain confidential, secure records
RA 10029 (Philippine Psychology Act)
- • Psychologist: MA/MS + licensure (full scope of practice)
- • Psychometrician: BS + licensure (testing under supervision)
- • Only licensed professionals can administer psychological tests
- • Code of Ethics mandated by Professional Regulation Commission
Key Takeaways
- ✓Reliability = consistency; Validity = accuracy
- ✓Cronbach's α ≥ .70 for internal consistency
- ✓Wechsler scales: WAIS (adults), WISC (children), WPPSI (preschool)
- ✓IQ scores: Mean = 100, SD = 15
- ✓MMPI-2: T ≥ 65 clinically significant
- ✓Rorschach: 10 inkblots; TAT: picture stories
- ✓WCST & Trail Making: frontal lobe/executive function
- ✓Only licensed psychologists/psychometricians can test