A critical review of scales of activities of daily living (Law & Letts, 1989)

Law, M., & Letts, L. (1989). A critical review of scales of activities of daily living. American Journal of Occupational Therapy, 43(8), 522-528.

Department of Medicine, McMaster University, Hamilton, Ontario, Canada.

Abstract: Occupational therapists routinely perform activities of daily living (ADL) assessments. Although the literature contains many ADL scales, few sources summarize and review the measurement properties of such scales. In this paper, standard criteria are used to review scales of basic self-care. Each scale is critically appraised regarding its purpose, clinical utility, construction, standardization, reliability, and validity. Recommendations are made regarding the ADL scales that are most suitable for describing, predicting, or evaluating ADL function. This review is intended to help therapists in selecting the most appropriate ADL measure to use in their clinical practice.

http://www.ncbi.nlm.nih.gov/pubmed/2672821

My notes:

This is a review paper for ADL scales.

The problems associated with ADL scale is that there are too many of them but not too many of them have been validated. In addition, many authors would simply select the items they want to include from existing instruments which causes problems in scale reliability and validity.

In addition, the instruments are "symptom-centered" rather than "client-centered." In other words, items included in the scale might not reflect what the patients really want…

There is a lack of a universal disability framework although there does exist a diagnostic framework in that most scales are often constructed and validated for patients of specific age groups or with certain diagnosis.

The scales were reviewed based on 6 main questions:

1. What is the purpose of the scale?
   
   1. Description, prediction or evaluation? see http://ratologydisabled.blogspot.com/2009/03/evaluating-activities-of-daily-living.html
2. Is the scale clinically useful?
   
   1. Some scales are too short and others either too complex or too long
   2. Existing research found that incongruence between observations of the professionals and those reported by the patients.
      
      1. Klein-Parris, Clermount-Michel, and O'Neill (1986) found that higher accuracy of assessment was associated with high functional patients and low complexity in the items
      2. McGinnis, Seward, DeJong, and Osberg (1986) made comparison between the rating of professionals and the patients using the Barthel Index. They found self-reported scores to be lower.
3. Was the scale construction adequate?
   
   1. Are items selected based on expert opinions or statistical properties for their discriminability, predictability or evaluate-ability?
   2. Level of measurement? Nominal, ordinal, interval or ratio?
   3. Item weighting? And, does the weighting make any difference?
4. Is the scale standardized?
   
   1. Has there been research done to establish the reliability and validity of the scale?
5. Is the scale reliable?
   
   1. How is the reliability derived? Is the statistics appropriate?
6. Is the scale valid?
   
   1. Content validity? Does the instrument cover the whole domain (i.e., disability)?
   2. Construct validity? Are you really measuring what you thought you are meaning?
   3. Criterion? Is there any criterion measure that have been determined as valid measure in the domain?

Please check Table 1 in the main article for the results of the analyses and the concluding paragraphs for the authors' recommendations concerning these ADL scales reviewed in this article.