Improving measurement of ADLs

1. Activites of daily living
Roger Watson
Professor of Nursing
Symposium: Medicine for the elderly
Royal College of Physicians of Edinburgh
12 April 2013

2. ADL
The activities usually performed in the course of a normal day
in a person's life, such as:
• Eating
• Toileting
• Dressing
• Bathing
• Brushing the teeth.

3. ADL
• The ability to perform ADL may be compromised by a
variety of causes, including chronic illnesses and accidents.
• The limitation may be temporary or permanent;
rehabilitation may involve relearning the skills or learning
new ways to accomplish ADL.

4. • .

5. What do we want from an ADL scale?
• Utility
• Meaningful scoring system
• Predictive ability

6. Townsend Functional Ability Scale
1) Cut toe nails
2) Shop with bags
3) Up and down stairs
4) Get on bus
5) Reach overhead
6) Wash or bathe
7) Tie a knot
8) Prepare a meal
9) Heavy housework
No difficulty = 0
With difficulty = 1
Unable to do = 2
Fieo R, Watson R, Deary IJ, Starr JM (2009) A revised activities of daily
living instrument increases interpretive power: theoretical applications
for functional tasks exercise Gerontology 56: 483-490
Watson R, van der Ark LA, Lin L-C, Fieo R Deary IJ Meier R (2011) Item
response theory: How Mokken scaling can be used in clinical
practiceJournal of Clinical Nursing 21: 2736-2746

7. Utility
KISS = Keep it Short and Simple
In the Townsend Functional Ability Scale 6 items form a
reliable hierarchy using item response theory (Fieo et al
2009)

8. Townsend Functional Ability Scale
Mean
1) Cut toe nails 0.72
3) Up and down stairs 0.36
4) Get on bus 0.22
4) Reach overhead 0.16
5) Wash or bathe 0.09
6) Tie a knot 0.04
n=548 Community dwelling
older people
Fieo R, Watson R, Deary IJ, Starr JM (2009) A revised activities of daily
living instrument increases interpretive power: theoretical applications
for functional tasks exercise Gerontology 56: 483-490

9. Meaningful scoring system
Obtained if the items in the ADL scale are ordered along the
disability trait
In the Townsend Functional Ability Scale the 6 items are
ordered for every person at all levels of disability (Watson et
al 2011)

10. Invariant item ordering
P
Disability
Cut toe
nails
Tie a
knot
Watson R, van der Ark LA, Lin L-C, Fieo R Deary IJ Meier R
(2011) Item response theory: How Mokken scaling can be used
in clinical practice Journal of Clinical Nursing 21: 2736-2746

11. Meaningful scoring system
What does a non-meaningful scoring system look like?

12. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails
2) Up and down stairs
3) Get on bus
4) Reach overhead
5) Wash or bathe
6) Tie a knot
Total score =
No difficulty = 0
With difficulty = 1
Unable to do = 2

13. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 0
No difficulty = 0
With difficulty = 1
Unable to do = 2

14. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 12
No difficulty = 0
With difficulty = 1
Unable to do = 2

15. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 6
No difficulty = 0
With difficulty = 1
Unable to do = 2

16. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 6
No difficulty = 0
With difficulty = 1
Unable to do = 2

17. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 6
No difficulty = 0
With difficulty = 1
Unable to do = 2

18. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 6
No difficulty = 0
With difficulty = 1
Unable to do = 2

19. Meaningful scoring system
What does a meaningful scoring system look like?

20. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 0
No difficulty = 0
With difficulty = 1
Unable to do = 2

21. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 1
No difficulty = 0
With difficulty = 1
Unable to do = 2

22. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 2
No difficulty = 0
With difficulty = 1
Unable to do = 2

23. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 3
No difficulty = 0
With difficulty = 1
Unable to do = 2

24. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 4
No difficulty = 0
With difficulty = 1
Unable to do = 2

25. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 5
No difficulty = 0
With difficulty = 1
Unable to do = 2

26. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 6
No difficulty = 0
With difficulty = 1
Unable to do = 2

27. Townsend Functional Ability Scale
Does the patient ever:
None Some Unable
1) Cut toe nails 
2) Up and down stairs 
3) Reach overhead 
4) Get on bus 
5) Wash or bathe 
6) Tie a knot 
Total score = 7
No difficulty = 0
With difficulty = 1
Unable to do = 2

28. Predictive ability
Picks up disability early
The Townsend Functional Ability Scale
1) Cut toe nails
2) Up and down stairs
3) Reach overhead
4) Get on bus
5) Wash or bathe
6) Tie a knot

29. What do we want from an ADL scale?
• Utility
• Meaningful scoring system
• Predictive ability

30. r.watson@hull.ac.uk
@rwatson1955