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Psychometric properties of the Satisfaction With Life Scale in Parkinson's disease
Author(s) -
Rosengren L.,
Jonasson S. B.,
Brogårdh C.,
Lexell J.
Publication year - 2015
Publication title -
acta neurologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.967
H-Index - 95
eISSN - 1600-0404
pISSN - 0001-6314
DOI - 10.1111/ane.12380
Subject(s) - cronbach's alpha , intraclass correlation , reliability (semiconductor) , psychometrics , scale (ratio) , psychology , statistics , standard error , life satisfaction , clinical psychology , medicine , mathematics , social psychology , cartography , geography , power (physics) , physics , quantum mechanics
Objective The Satisfaction With Life Scale ( SWLS ) is a global measure of life satisfaction ( LS ). The objective of this study was to evaluate the psychometric properties (data completeness, scaling assumptions, targeting and reliability) of the SWLS in a sample of people with Parkinson's disease ( PD ). Materials and Methods A postal survey including a Swedish version of the SWLS and demographic information was administered to 174 persons with PD ; 97 responded and received a second survey after 2 weeks. Results The mean ( SD ) age and PD duration of the 97 responders were 73 (8) and 7 (6) years, respectively. Data completeness was 92% to 97% for the five items in the SWLS and 92% for the total score (5–35 points). The mean score of the SWLS was 24.2 points (7.7), indicating that this group had an average LS . The items’ means and SD s were roughly parallel and the score distribution was even. The internal consistency reliability (Cronbach's alpha) was 0.90. The test–retest reliability, assessed by the intraclass correlation coefficient, was 0.78. The scale showed no systematic difference between the first and second response. The standard error of measurement was 3.6 points, and the smallest detectable difference was 10.0 points. Conclusions This evaluation of the psychometric properties of the SWLS shows that the scale has good data completeness, scaling assumptions and targeting and that the internal consistency reliability and the test–retest reliability are acceptable. Thus, the SWLS is a psychometrically sound and suitable tool to asses LS in people with PD .