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The Katz Index of Independence in Activities of Daily Living (Katz ADL) is a six-item scale that measures a patient’s ability to perform basic self-care tasks without help, scored from 0 to 6. This page covers the six items, standard scoring, score interpretation, the Modified Katz scale, and how it differs from the Lawton Instrumental Activities of Daily Living Scale, which measures higher-order community-living tasks rather than basic self-care. For related bedside functional-status instruments, see CASRAI’s Barthel Index and Functional Independence Measure pages.
What the Katz ADL is, and who built it
The Katz Index was developed by Sidney Katz and colleagues and published in 1963 (Katz S, Ford AB, Moskowitz RW, Jackson BA, Jaffe MW, “Studies of Illness in the Aged: The Index of ADL: A Standardized Measure of Biological and Psychosocial Function,” JAMA 185(12):914–919), originally built at the Benjamin Rose Hospital in Cleveland to track recovery in patients with hip fractures and other conditions affecting mobility. It remains one of the most widely used and cited instruments for basic functional status in older adults, and like the Barthel Index, it is free to use and reproduce — there is no license fee or required certification, which is part of why it appears so consistently across nursing assessments, geriatric consult notes, and published research.
The six items and scoring
Each of the six functions is scored as 1 point (independent) or 0 points (dependent, i.e. needing supervision, direction, or personal assistance). The total ranges from 0 to 6.
| Item | What it assesses |
|---|---|
| Bathing | Washing the whole body, independently or needing help with only a single part (e.g. the back) |
| Dressing | Getting clothes from closets/drawers and putting them on, including managing fasteners |
| Toileting | Getting to and from the toilet, cleaning oneself, and managing clothing |
| Transferring | Moving in and out of a bed or chair without help |
| Continence | Complete self-control of bowel and bladder function |
| Feeding | Getting food from a plate into the mouth without help (food preparation is not included) |
Interpreting the total score
The commonly cited interpretation, consistent across published nursing and geriatric references, is:
- 6: full function — independent in all six activities
- 4: moderate functional impairment
- 2 or less: severe functional impairment, high dependency
Because the instrument is scored in whole-point, single-item increments rather than a graded response scale, it has a ceiling effect similar to the original (unmodified) Barthel Index: it distinguishes dependency levels well among more impaired patients, but two patients who both score 4 or 5 may still differ meaningfully in the amount of assistance they actually need, since the item score does not capture partial or intermittent assistance beyond the independent/dependent split.
The Modified Katz scale
A modified version of the scale exists and is sometimes cited in professional references (e.g. the Merck Manuals’ Modified Katz Activities of Daily Living Scale), which grades responses within each item rather than using the original’s strict independent/dependent split, intended to capture partial assistance the original scale’s binary scoring misses. As with the Modified Barthel Index, more than one modified scoring convention circulates in practice, so a chart or protocol citing “Modified Katz” should specify exactly which version and point scheme it used before comparing scores across units or facilities.
Katz ADL vs. Lawton IADL
The Katz ADL and the Lawton Instrumental Activities of Daily Living (IADL) Scale are frequently used together in a comprehensive geriatric assessment, but they measure different tiers of function. The Katz ADL assesses basic self-care tasks — bathing, dressing, toileting, transferring, continence, and feeding — that are physically and cognitively simpler and are typically the last abilities lost as a person’s function declines. The Lawton IADL assesses more complex, higher-order tasks needed for independent community living — using a telephone, shopping, preparing food, housekeeping, doing laundry, arranging transportation, managing medications, and handling finances — that generally require more cognitive involvement and are typically lost earlier in the disablement process. A patient who is independent on the Katz ADL but impaired on the Lawton IADL is a common and clinically meaningful pattern, not a contradiction between the two tools.
Reliability and what it misses
The Katz ADL is quick to administer (commonly a few minutes) via direct observation, patient or caregiver interview, or review of recent documented performance, and it has been used and validated across a large body of published research since 1963. Its main limitations mirror those of other basic-ADL instruments: it does not assess cognition, mood, or instrumental activities of daily living, and because it is scored in coarse whole-item increments, it is not sensitive to small functional changes within the independent-to-dependent range for any single activity.
Use in nursing assessment and care planning
Beyond tracking functional recovery, the Katz ADL is used in nursing home admission and care-planning assessments, hospital discharge-planning decisions, and home-care eligibility evaluations, where a low score is one of the factors supporting a recommendation for a higher level of supervised or supported care. As with any functional score that feeds a downstream care decision, the same chart-audit discipline applies as with other bedside instruments: confirm the score reflects the patient’s actual current ability (not a stale prior assessment) and that it was completed on the interval the facility’s assessment policy requires.
Frequently asked questions
What is a normal Katz ADL score?
A score of 6 indicates full function and complete independence across all six basic activities of daily living. A score of 4 indicates moderate functional impairment, and a score of 2 or less indicates severe impairment and high dependency.
What are the six activities assessed by the Katz ADL?
Bathing, dressing, toileting, transferring, continence, and feeding. Each is scored 1 point if the patient is independent and 0 points if they need supervision, direction, or assistance, for a total range of 0 to 6.
What is the difference between the Katz ADL and the Lawton IADL?
The Katz ADL measures basic self-care tasks (bathing, dressing, toileting, transferring, continence, feeding) that are typically the last abilities a person loses as function declines. The Lawton IADL measures more complex tasks needed for independent community living (telephone use, shopping, food preparation, housekeeping, laundry, transportation, medication management, and finances) that are typically lost earlier. The two scales are often used together, not as substitutes for each other.
Is the Katz ADL a licensed or proprietary instrument?
No. Like the Barthel Index, the Katz ADL is free to use and reproduce, with no license fee or required certification — unlike the Functional Independence Measure (FIM), which is a proprietary instrument licensed through UDSMR.
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