title: Validity and reliability of the instrument Performance and Satisfaction in Activities of Daily Living (PS-ADL) and its clinical applicability to adults with rheumatoid arthritis.
abstract: OBJECTIVE
  This study set out to evaluate the validity and reliability of the instrument Performance and Satisfaction of Activities of Daily Living (PS-ADL) in patients with rheumatoid arthritis (RA). The PS-ADL is a questionnaire including 39 actions divided into 12 activities measuring the degree of difficulty and satisfaction with activity performance.
  
  
  METHODS
  Construct validity was examined by factor analysis. For convergent and discriminant validity evaluation, the Performance and the Satisfaction scales were correlated to the Health Assessment Questionnaire (HAQ), the Rheumatoid Arthritis Self-Conception (RASC), pain, fatigue, and mobility. Internal consistency was tested and repeated measurements were taken to establish the Percentage Agreement (PA) and correlation coefficients for test-retest reliability.
  
  
  RESULTS
  The factor analysis revealed the PS-ADL scale to be unidimensional. Significant correlations were seen between the Performance and Satisfaction scales and the HAQ (r(s) 0.78, 0.67), and between the RASC and Satisfaction scale (r(s) 0.45). Cronbach's alpha level ranged from 0.41 to 0.92 for the Performance scale and 0.66 to 0.94 for the Satisfaction scale. The percentage agreement (PA) at action level ranged from 68% to 91% for the Performance scale and from 59% to 91% for the Satisfaction scale.
  
  
  CONCLUSIONS
  The PS-ADL is a valid instrument with satisfactory reliability. It is easy to handle and can be recommended for use in RA patients.
authors.affiliation: Sahlgrenska University Hospital, Department of Occupational Therapy and Rheumatology, Göteborg, Sweden.
authors.forename: Birgitha
authors.initials: B
authors.lastname: Archenholtz
authors.forename: Berit
authors.initials: B
authors.lastname: Dellhag
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid; D001294:Attitude to Health; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012648:Self Care; D011795:Surveys and Questionnaires