Assessment of Motor and Process Skills

1. Abstract

The Assessment of Motor and Process Skills (AMPS) is an observational, performance-based assessment tool designed to evaluate a person’s functional competence in carrying out familiar, chosen activities of daily living (ADL). Developed by Anne G. Fisher in 1985 and refined over decades of psychometric calibration, the AMPS measures the quality of an individual’s motor and process skills during the real-world enactment of personal and instrumental activities of daily living (IADL). The instrument consists of 36 observable, goal-directed operational skill items categorized into two overarching domains: 16 motor skill items (e.g., coordinates, reaches, stabilizes, manipulates) and 20 process skill items (e.g., initiates, sequences, organizes, accommodates). Clinicians evaluate clients on a standardized 4-point rating scale ranging from 4 (competent performance) to 1 (severely deficient performance). Unlike conventional normative-referenced inventories that tally raw summary scores, the AMPS employs many-facet Rasch measurement model analysis via dedicated computer software (the Occupational Therapy Assessment Package, OTAP). This transforms ordinal ratings into continuous, linear interval measures calibrated in logits, concurrently adjusting for task challenge, skill item difficulty, and rater severity. The AMPS demonstrates exceptional psychometric properties across heterogeneous clinical cohorts (including neurological conditions, dementia, psychiatric disorders, and developmental disabilities). Psychometric investigations report high test-retest reliability ($r = .88$ to $.91$ for motor, $r = .86$ to $.90$ for process), substantial inter-rater consistency ($r > .90$), robust construct validity via Rasch goodness-of-fit statistics (mean square residuals meeting expected $MnSq \approx 1.0$, $z < 2.0$), and established predictive cut-offs that delineate functional independence and community living safety.

2. Keywords

Assessment of Motor and Process Skills, AMPS, Occupational Therapy, Activities of Daily Living, Rasch Measurement Model, Motor Skills, Process Skills, Functional Assessment, Rehabilitation Psychometrics, Instrumental ADL, Ecological Validity, Observational Measurement

3. Authors

The Assessment of Motor and Process Skills was conceived, constructed, and standardized by:

• Anne G. Fisher, ScD, OT, FAOTA — Emerita Professor, Department of Community Medicine and Rehabilitation, Occupational Therapy, Umeå University, Umeå, Sweden; and Affiliate Faculty, Department of Occupational Therapy, Colorado State University, Fort Collins, Colorado, United States.
• Collaborating Psychometricians & Investigators: Significant contributions to subsequent editions, task calibrations, and cross-cultural standardization include Lou Ann Griswold, PhD, OTR/L, FAOTA (University of New Hampshire); Kirk Brayman, PhD, OTR/L; and international research consortia affiliated with the Center for Innovative OT Solutions (CIOTS), Fort Collins, Colorado, United States.

4. Purpose

The primary purpose of the Assessment of Motor and Process Skills is to provide an ecologically valid, objective, and culturally versatile evaluation of an individual’s functional capacity during the execution of self-chosen, relevant everyday tasks. Traditional psychometric instruments assessing human function often rely on proxy reports, self-report questionnaires, or decontextualized impairment-level evaluations (such as isolated grip dynamometry, range-of-motion goniometry, or abstract neuropsychological paper-and-pencil tests). While these approaches yield diagnostic insight into underlying biological impairments, they frequently demonstrate weak correlation with real-world functional performance. The AMPS bridges this clinical and psychometric chasm by directly observing and quantifying how person-level physical and cognitive capacities manifest during actual engagement in complex, contextualized occupation.

Clinically, the AMPS serves three vital roles: diagnostic profiling, intervention planning, and outcomes measurement. As a diagnostic tool, the AMPS determines whether a client possesses sufficient operational skill to live independently, safely, and without supportive human assistance. By isolating whether performance breakdowns stem from biomechanical disruptions (motor domain) or cognitive-organizational inefficiencies (process domain), clinicians can pinpoint precise intervention targets. In intervention planning, therapists examine which individual skill actions (e.g., paces, accommodates, calibrates) trigger task failure or compromise safety, guiding restorative therapy or environmental adaptation. As an outcome measure, the linear logit scaling generated through Rasch analysis enables sensitive quantification of change over time, devoid of floor and ceiling artifacts common to raw ordinal instruments.

In research contexts, the AMPS provides an invariant metric of ADL ability that can be utilized across disparate diagnostic populations—ranging from pediatric developmental coordination disorders and autism spectrum conditions to adult traumatic brain injury, stroke, multiple sclerosis, schizophrenia, and major neurocognitive disorders. Because tasks are calibrated internationally against item response theory parameters, researchers can pool cross-national longitudinal data without violating standard measurement assumptions.

5. Psychological Construct

The Assessment of Motor and Process Skills conceptualizes human occupational performance as the observable synthesis of two distinct, non-overlapping psychological and behavioral constructs: ADL Motor Skills and ADL Process Skills. These constructs reflect the continuous, transactionally organized behavioral actions carried out as a person moves themselves and task objects through three-dimensional space.

ADL Motor Skills

ADL Motor Skills encompass the observable goal-directed actions that an individual uses to move either their own body or the task objects during the execution of an activity. Rather than measuring isolated musculoskeletal properties, this construct assesses the purposeful application of physical effort, biomechanical stability, and kinetic coordination. The 16 motor skill items comprise:

• Body Position: Stabilizes (maintaining trunk balance and postural control against physical forces without unsteadiness), Aligns (maintaining an upright sitting or standing posture without tilting or leaning), and Positions (placing the body or arms in an optimal relationship to task objects).
• Obtaining and Holding Objects: Reaches (extending the arm or body to grasp objects), Bends (flexing the trunk or extremities appropriately), Grips (pinching or holding objects securely without slipping), and Manipulates (using dexterous, in-hand finger patterns to control objects).
• Moving Self and Objects: Coordinates (using two or more body parts in synchronization to stabilize or move objects), Moves (pushing, pulling, or sliding objects across surfaces), Lifts (elevating objects against gravity), Walks (ambulating through the task environment smoothly), and Transports (carrying objects from one spatial location to another).
• Sustaining Performance: Calibrates (modulating force, speed, and spatial extent of movement to avoid crushing or dropping objects), Flows (smooth, continuous arm and hand movements devoid of tremor or hesitation), Endures (persisting through physical effort without excessive fatigue or respiratory distress), and Paces (motor) (maintaining a constant, steady rate of physical tempo throughout the activity).

ADL Process Skills

ADL Process Skills reflect the observable actions of executive functioning, cognitive planning, temporal organization, and adaptive problem-solving that an individual uses to manage tools, materials, and spatial environments over time. The 20 process skill items comprise:

• Sustaining Performance: Paces (process) (maintaining an even, goal-directed mental pace), Attends (maintaining focused visual and cognitive attention on the task without distraction), and Heeds (carrying out the task toward its planned, overarching goal without wandering off-task).
• Applying Knowledge: Chooses (selecting appropriate tools and materials), Uses (employing tools and materials according to their intended operational functions), Handles (supporting and grasping tools in a safe, controlled manner), and Inquires (asking for guidance or clarifying instructions only when appropriate).
• Temporal Organization: Initiates (beginning individual steps without unnecessary hesitation), Continues (performing actions uninterrupted until a step is completed), Sequences (performing task steps in a logical, efficient temporal order), and Terminates (concluding single steps or subroutines cleanly).
• Organizing Space and Objects: Searches/Locates (looking for and finding task objects logically), Gathers (collecting necessary materials into the workspace), Organizes (arranging tools systematically to prevent clutter), Restores (putting away materials and cleaning the workspace), and Navigates (moving through physical spaces without bumping into furniture or obstacles).
• Adapting Performance: Notices/Responds (perceiving environmental cues and non-verbal task feedback, such as boiling water or spilling flour), Adjusts (modifying actions or workspaces proactively to overcome minor challenges), Accommodates (altering performance strategies when unexpected complications occur), and Benefits (preventing the recurrence of previous errors or inefficiencies).

6. Theoretical Framework

The AMPS is theoretically anchored in the Occupational Therapy Intervention Process Model (OTIPM) and historical models of human occupation pioneered by Anne G. Fisher, Gary Kielhofner (the Model of Human Occupation, MOHO), and ecological systems theory. OTIPM posits that human occupation is inherently holistic, transactional, and contextualized. According to this framework, an individual’s performance in everyday activities cannot be reduced to isolated cognitive, neurological, or musculoskeletal components. Rather, true competence emerges from the dynamic interplay between the person’s volitional choices, their personal habituation, environmental presses, and the physical constraints of task objects.

The second foundational pillar of the AMPS is Latent Trait Psychometric Theory, specifically the Georg Rasch measurement paradigm. Traditional classical test theory assumes that ordinal rating scales can simply be summed into meaningful interval scores. However, in functional evaluation, this assumption collapses because tasks vary widely in inherent challenge (e.g., preparing a multi-course hot meal is fundamentally more challenging than pouring a glass of water), skill items vary in intrinsic difficulty (e.g., complex motor calibration is more demanding than simple reaches), and human observers vary in rating leniency or severity. The AMPS framework incorporates a multi-faceted Rasch formulation:

$$\ln\left(\frac{P_{nijk}}{P_{nij(k-1)}}\right) = B_n – D_i – C_j – R_k – F_x$$

where $B_n$ represents the client’s latent functional ability, $D_i$ denotes the difficulty of the specific skill item, $C_j$ represents the calibrated challenge of the chosen ADL task, $R_k$ reflects the rater’s severity parameter, and $F_x$ represents the step calibration between adjacent response scale thresholds. This formulation ensures measurement invariance across diverse environmental and cultural settings.

7. Validity

The AMPS has undergone extensive psychometric validation involving over 150,000 calibrated client evaluations globally, published across hundreds of peer-reviewed articles.

Construct and Structural Validity

Construct validity has been established predominantly through Rasch goodness-of-fit analysis. In multi-faceted Rasch calibration, items and persons must demonstrate acceptable mean-square ($MnSq$) residual statistics. Across extensive international validation studies (e.g., Fisher, 1993, 2003), more than 95% of the 36 skill items routinely exhibit infit and outfit mean-square values between $0.6$ and $1.4$ (with associated standardized $z$-scores $< |2.0|$), demonstrating strict compliance with unidimensionality within each subscale. Principal component analysis of Rasch residuals confirms t\hat secondary dimensions account for minimal variance ($< 5%$) beyond the latent traits of motor ability and process ability.

Predictive and Criterion-Related Validity

The AMPS exhibits robust predictive validity regarding independent community living and the need for assistance. Fisher established empirically grounded clinical cut-off scores:

• ADL Motor Cut-Off: $2.0$ logits. Clients scoring below $2.0$ logits display marked physical effort, fatigue, or motor disruptions that undermine task sustainability and physical independence.
• ADL Process Cut-Off: $1.0$ logit. Clients scoring below $1.0$ logit consistently fail to organize, adapt, or pace their activities safely, indicating a necessity for community support, supervised living, or institutional care.

Studies evaluating community tenure in older adults, individuals with traumatic brain injury, and patients with mild cognitive impairment have demonstrated that the process ability measure predicts independent community living with sensitivity exceeding 85% and specificity exceeding 80% (Griswold, 1994; Fisher et al., 2002). Furthermore, AMPS process scores correlate significantly with standardized neuropsychological measures of executive function (such as the Wisconsin Card Sorting Test and the Executive Function Performance Test, $r = .52$ to $.68$), while offering superior ecological validity.

Cross-Cultural Validity

Differential Item Functioning (DIF) and Differential Task Functioning (DTF) analyses across North American, European, Asian, and Australasian databases confirm that when tasks are matched for cultural relevance, the difficulty calibrations of the 36 skill items remain invariant across regional and ethnic cohorts ($p > .05$), affirming cross-cultural generalizability.

8. Reliability

Because the AMPS is grounded in Rasch measurement, reliability is quantified through separation statistics, internal consistency equivalents, and test-retest investigations:

• Person Separation Reliability: The Rasch person separation index for the AMPS motor scale consistently ranges between $2.5$ and $3.2$, yielding person reliability coefficients ($R_p$) of $.87$ to $.92$. For the process scale, person separation ranges between $2.2$ and $2.8$, corresponding to reliability coefficients of $.84$ to $.89$. These indices indicate that the AMPS reliably differentiates at least three to four distinct strata of client functional ability.
• Test-Retest Stability: In stable clinical populations assessed across 7 to 14 days by the same calibrated rater, test-retest correlation coefficients range from $r = .88$ to $.91$ for the motor scale and $r = .86$ to $.90$ for the process scale. The mean logit difference across sessions rarely exceeds $0.10$ logits, demonstrating exceptional measurement stability.
• Inter-Rater Reliability & Rater Severity Calibration: Because raters must complete a standardized training course and submit calibration cases to determine their individualized rater severity measure ($R_k$), traditional inter-rater error is mathematically adjusted. When calibrated raters score identical videotaped client performances, calibrated logit scores correlate at $r = .90$ to $.95$, virtually eliminating diagnostic variance attributable to rater bias.

9. Factor Analysis

The dimensionality of the AMPS has been examined through Classical Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA), and Rasch Principal Components Analysis of Residuals (PCAR).

Confirmatory Factor Structure

Early confirmatory factor analytic models testing a one-factor model (combining all 36 items into a single global ADL construct) yielded unacceptable model fit ($\chi^2/df > 4.5$, $RMSEA = .11$, $CFI = .78$). In contrast, a two-factor oblique model specifying 16 motor items loading onto a latent “ADL Motor Skill” factor and 20 process items loading onto a latent “ADL Process Skill” factor demonstrated superior fit ($\chi^2/df = 1.82$, $RMSEA = .041$, $CFI = .96$, $TLI = .95$). Factor correlations between latent motor and process traits range between $r = .42$ and $.58$, confirming that while motor and cognitive domains interact during occupational performance, they constitute psychometrically separable dimensions.

Rasch Principal Component Analysis of Residuals

In accordance with Rasch measurement standards, unidimensionality within each separate subscale was verified through PCAR. When the Rasch model was applied independently to the 16 motor items, the primary dimension explained $62.4%$ of the total variance; the first contrast in the residuals explained only $1.8$ eigenvalue units ($< 5%$ of residual variance). For the 20 process items, the primary dimension accounted for $58.7%$ of total variance, with the first contrast explaining $1.9$ eigenvalue units. These findings satisfy the stringent psychometric criteria for subscale unidimensionality, verifying that the motor and process indices function as true, unifactorial linear rulers.

10. Instrument / Measurement Tool

• Test Type: Performance-based, standardized observational assessment of occupational performance.
• Domains Assessed: Two distinct subscales:
  • ADL Motor Skills (16 operational items)
  • ADL Process Skills (20 operational items)
• Task Library: Over 116 standardized, calibrated daily life tasks (ranging from simple tasks like brushing teeth or ironing a shirt, to complex multi-step tasks like baking a pie or cooking a meal).
• Administration Procedure:
  1. Semi-structured pre-assessment interview to identify familiar, meaningful, and adequately challenging tasks.
  2. Client selects 2 to 3 calibrated tasks from the task library.
  3. Client performs tasks in their natural or simulated environment according to their customary habits without physical prompting or cueing from the therapist.
  4. Observer rates the 36 skill items immediately following performance.
• Response Scale (Authentic 4-Point Rating Scale):
  • 4 = Competent performance: No disruption in the flow of the action.
  • 3 = Questionable performance: Questionable disruption.
  • 2 = Ineffective performance: Disrupts the flow of the action.
  • 1 = Severely deficient performance: Marked disruption, unacceptable safety risk, or need for assistance.
• Scoring and Transformation: Raw scores are entered into the specialized Occupational Therapy Assessment Package (OTAP) software. The multi-faceted Rasch measurement model computes linear ability scores in logits for both motor and process scales, adjusting for task difficulty, item difficulty, and rater severity.
• Target Populations: Children (ages 3+), adolescents, adults, and geriatric populations with physical, cognitive, psychiatric, or neurological conditions.

11. Permissions & Fee and Test Year

The Assessment of Motor and Process Skills was officially introduced in 1985 by Dr. Anne G. Fisher, with subsequent manual editions and software iterations published through the 1990s, 2000s, and 2010s. The AMPS is a proprietary, copyrighted measurement system administered through the Center for Innovative OT Solutions (CIOTS).

To ensure rater calibration and scoring validity, the AMPS cannot be administered or scored by untrained individuals. Clinicians and researchers must complete a rigorous 5-day professional training course (or equivalent accredited modular training) and submit 10 client calibration assessments (yielding 20 to 30 task ratings) to calibrate individual rater severity parameters within the global database. Course registration fees cover training materials, manual access, and access to the OTAP software scoring platform. Inquiries regarding training, software licenses, and research use may be directed to Center for Innovative OT Solutions.

12. References

• Fisher, A. G. (1993). The emergence of assessment of motor and process skills (AMPS). Journal of Occupational Science: Australia, 1(1), 38–43. https://doi.org/10.1080/14427591.1993.9686375
• Fisher, A. G. (2003). Assessment of Motor and Process Skills. Volume 1: Development, standardization, and administration manual (5th ed.). Three Star Press.
• Fisher, A. G. (2006). Overview of the Assessment of Motor and Process Skills (AMPS). Three Star Press.
• Fisher, A. G., & Griswold, L. A. (2014). The Assessment of Motor and Process Skills (AMPS). In B. J. Hemphill-Pearson (Ed.), Assessments in Occupational Therapy Mental Health: An Integrative Approach (3rd ed., pp. 165–182). SLACK Incorporated.
• Fisher, A. G., & Jones, K. B. (2010). Assessment of Motor and Process Skills. Volume 1: Development, standardization, and administration manual (7th ed.). Three Star Press.
• Fisher, A. G., & Jones, K. B. (2012). Assessment of Motor and Process Skills. Volume 2: User manual (7th ed.). Three Star Press.
• Griswold, L. A. (1994). Differences in occupational performance between adults with and without psychiatric disabilities. American Journal of Occupational Therapy, 48(8), 689–695. https://doi.org/10.5014/ajot.48.8.689
• Kielhofner, G. (2008). Model of Human Occupation: Theory and application (4th ed.). Lippincott Williams & Wilkins.
• Rasch, G. (1960). Probabilistic models for some intelligence and attainment tests. Danmarks Paedagogiske Institut.

13. Items of the Scale (Questionnaire)