Katz Index of Independence in ADLs

Overview

Author(s): Katz, S., Ford, A.B., Moskowitz, R.W., Jackson, B.A., & Jaffe, M.W.

Year of Publication: 1970 (originally 1963)

Publisher: The Gerontologist Journal 

Type of Assessment: Performance measure

• Observation-based

• Standardized

Cost: Free

How to Access: https://www.alz.org/careplanning/downloads/katz-adl.pdf 

Age: Elderly Adults/Geriatrics (18-65+)

Diagnoses: Age-related concerns & chronically ill

Setting: Skilled nursing facilities, long-term acute care, home health, inpatient rehab

Areas Assessed:

• Activities of daily living

  • Bathing

  • Dressing

  • Toileting

  • Transferring

  • Continence

  • Feeding

• Motor functioning

Administration

Time: >5 mins - depends on the client's abilities for task performance

Group/Individual: Individual

Subtests: 6

Instructions: The assessment is administered through observation of client's performance.

• Clients are classified as being "dependent", requiring assistance, or "independent"

Materials: Evaluation form, pencil, additional ADL materials as needed

User Qualifications: N/A

Scoring Procedures

How to Score: Clients are scored as being "dependent" or "independent" if they can complete tasks with/without supervision, direction or personal assistance, respectively, with a "yes"/"no"

• Overall cores range from 0 to 6

  • 0 = completely dependent

  • <2 = severe functional impairment

  • 4 = moderate impairment

  • 6 = completely independent

Score Indications: Higher scores (6) indicate greater or complete independence in completing ADL tasks while lower scores are indicative of needing assistance.

Psychometrics

Reliability: Excellent 

• Interrater reliability: scores are consistent across different evaluators when evaluating the same person's ADL performance

  • ICC=0.95; 0.999, 95% CI

• Test-retest reliability: when the same individual is assessed multiple times under similar conditions, the results remain consistent over time

  • ICC = 1.00, 95% CI

  • r = 0.944

• Internal consistency: all the items (ADL tasks) within the assessment measure the same underlying concept—functional independence—reliably and consistently

  •  Cronbach's alpha = 0.838; α = 0.88

Validity: Adequate

• Predictive validity - how well an assessment or test can predict future outcomes or behaviors based on current test scores: scores can forecast future changes in that person's functional status.

  • Mobility = 0.5033

  • House Confinement = 0.3882

• Face validity- does the test appear to measure what it claims to: clearly assesses basic daily living tasks 

• Construct Validity - does the test measure the theoretical concept it is supposed to: well-established construct of functional independence with scores that correlate with overall health status, functional decline, and need for assistance

  • r = 0.756 for men, r = 0.572 for women

• Concurrent Validity - does the test correlate well with other established measures: shown to correlate strongly with other functional assessments such as the Barthel Index & Lawton's IADL Scale

Pros & Cons

Strengths:

• Standardized 

• Free, easy to administer/score

• Reported in an easily understood manner across disciplines & professions via a common language

• Sensitive to declining health status

• Can provide baseline measurements to track progression or regression in functioning

Weaknesses: 

• Lacks sensitivity to detecting subtle changes in function

• Validity is adequate meaning it may not accurately measure what it is supposed to measure and may not capcute the intended constructs or predicts outcomes

• Ceiling effects - it only measures basic ADLs and does not have info regarding higher level ADLs & IADLs

• Does not capture a client's need for little assistance versus substantial assistance

• A full geriatric assessment should follow as this may not encompass all areas affecting functioning

References

• Asher, I. E. (2014). Asher’s occupational therapy assessment tools: An annotated index (4th ed.). AOTA Press.

• Shirley Ryan Ability Lab. (2016, December 1). Katz index of independence in activities of daily living. https://www.sralab.org/rehabilitation-measures/katz-index-independence-activities-daily-living 

• Wallace, M. & Shelkey, M. (2007). Katz index of independence in activities of daily living (ADL). The Hartford Institute for Geriatric Nursing, 2, 1-2. https://www.alz.org/careplanning/downloads/katz-adl.pdf