An assessment instrument is a tool designed to collect valid and reliable information about a person's abilities, behaviors, knowledge or skills in order to analyze them and make judgments about their development, learning or intervention needs.

- Validity: it actually measures what it intends to measure.

- Reliability: produces consistent results at different times or in different applications.

- Relevance: it is relevant to the purpose of the assessment.

- Standardization: follows uniform application and interpretation procedures.

- Objectivity: minimizes the influence of the evaluator's bias.

🔹 A) By area of development

1. Cognitive area.

- Assesses: attention, memory, reasoning, problem solving, academic skills.

- Examples: WPPSI-IV, WISC-V, Raven.

- Use: to detect intellectual strengths and weaknesses.

2. Motor area

- Evaluates: gross (walking, running, jumping) and fine (grasping, manual precision) coordination.

- Examples: Brunet-Lézine Psychomotor Development Scale, Denver Test II.

- Use: identify motor delays and plan stimulation.

3. Linguistic / communication area

- Evaluates: comprehension, oral expression, vocabulary, articulation and functional use of language.

- Examples: Peabody Picture Vocabulary Test (PPVT), CELF (Clinical Evaluation of Language Fundamentals).

- Use: diagnosis of language disorders and design of speech therapy intervention.

4. Social-emotional area

- Evaluates: emotional regulation, social skills, attachment, adaptive behavior.

- Examples: Conners Scale, Vineland Adaptive Behavior Scales, BASC-3.

- Use: to identify behavioral problems, anxiety, deficits in social interaction.

Adaptive / functional area

- Assesses: autonomy, self-care, practical daily living skills.

- Examples: ABAS-II (Adaptive Behavior Assessment System), Vineland-II.

- Use: support in the diagnosis of intellectual disability or ASD.

Instrument name: WPPSI-IV (Wechsler Preschool and Primary Scale of Intelligence - Fourth Edition)

Area assessed: Cognitive (general intelligence)

Age/population: Children aged 2 years 6 months to 7 years 7 months.

Description: Assesses cognitive skills such as verbal comprehension, fluid reasoning, working memory, and processing speed.

Example of use: To detect cognitive strengths and weaknesses in a 4 year old child in order to design early stimulation strategies.

Instrument name: Bayley Infant Development Scale (Bayley-III)

Area assessed: Cognitive, motor, socioemotional, and language.

Age/population: Children from 1 to 42 months.

Description: Standardized instrument that measures comprehensive early childhood development.

Example of use: To identify delays in fine motor development in an 18-month-old infant in order to recommend early stimulation activities.

- Muñiz, J. (2018). Introduction to psychometrics: classical theory and IRT. Ediciones Pirámide.

- Bayley, N. (2006). Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III). Harcourt Assessment.

- Wechsler, D. (2012). WPPSI-IV: Wechsler intelligence scale for preschool and elementary school-IV. Pearson.

1. Standardized tests

- Application under strict rules with normative scales.

- Example: WPPSI-IV, Bayley-III.

- Use: reliable clinical or academic diagnosis.

2. Checklists (Checklists)

- Set of items on observable behaviors.

- Example: Denver Developmental Checklist.

- Use: rapid screening in school or clinical settings.

Observational tools

- Based on systematic observation of the child in his natural environment or in a structured session.

- Example: anecdotal record, social interaction scales.

- Use: to assess play, interaction or spontaneous behavior.

Developmental scales

- Instruments that compare the child's development with chronological age parameters.

- Example: Bayley-III, Brunet-Lézine.

- Use: to identify global or specific delays.

5. Interviews

Obtaining information through structured, semi-structured or free-form questions to parents, teachers or caregivers.

- Example: K-SADS diagnostic interview.

- Use: to complement the assessment with background and context.

6. Questionnaires or self-reports

- The child himself (if old enough), parents or teachers answer about behaviors or symptoms.

- Example: Child Behavior Checklist (CBCL).

- Use: to assess perceptions, emotional and social behaviors.

7. Projective tests (in child psychology)

- Techniques that explore emotions, perceptions and personality through ambiguous stimuli.

- Example: Family Test, CAT (Children's Apperception Test).

- Use: to understand the child's internal experiences.