The Social Difficulties Inventory (SDI): development of subscales and scoring guidance for staff

Abstract

Aims: To develop subscales for clinical use of the Social Difficulties Inventory (SDI) with score interpretation guidance for use in routine oncology practice.Background: Patient-reported outcome measures are used increasingly in cancer care but successful implementation is dependent on a combination of sound psychometrics, guidance on clinical meaning and good clinical judgement. The SDI, a 21-item instrument (SDI-21) developed for use in cancer care, demonstrated good psychometric properties. Rasch analysis of the SDI resulted in a 16-item interval scale of Social Distress (SD-16), which allowed for establishment of some clinical utility guidance but further work was required to optimise meaningful interpretation in clinical practice.Data sources: Data were pooled from three studies investigating psychometrics and clinical utility of the SDI-21.Statistical analyses: Common factor analysis was undertaken on SD-16 items. Subscales were derived from the resulting factors and calculated by summing the scores of associated items. Subscale reliability was evaluated using Cronbach's a.Results: There were 652 participants. A three-factor model explaining 53.3% of the variance was extracted forming the basis of the subscales: Everyday living, Money matters and Self and others. Subscale reliability was good. In a clinical setting, a 2-point change in subscale score could be interpreted as a clinically meaningful difference.Conclusion: The development of three subscales and clinically significant difference scores for the SD-16, combined with the previously developed cut-off points, improves the clinical utility of the SDI-21 when assessing social issues in oncology care.

Translation of the Social Difficulties Inventory (SDI-21) into three south Asian languages and preliminary evaluation of SDI-21(Urdu)

“…A fixed three-factor model was extracted explaining 47.3% of the variance. The pattern matrix resembled previous analysis [13] with 13/16 items loading to the same factors. Reliability of the SD-16 (a = 0.852) and subscales (a = 0.792, 0.735 and 0.759, respectively) was good.…”

“…A 16-item summary index of Social Distress (SD-16), derived using Rasch analysis, functions equally for diagnostic group, disease stage, gender, age and level of deprivation [5]. Scoring recommendations for clinical use have been calculated [11][12][13].…”

“…1 Translation process [13]. Internal consistency of the SD-16 and original subscales (Everyday living, Money matters, Self and others) was evaluated using Cronbach's alpha with a lower acceptable limit of 0.7 [13].…”

“…Participant characteristics for data collated in the Rasch analysis Study 2 = clinical meaning and utility cross-sectional study(13) Study 3 = longitudinal study(11) Study 4 = Social impact of cancer on people of south Asian origin study including the additional 16 participants who completed SDI-21 (Urdu) only analysis suggested method of administration (read-aloud) may account for this. Over a third of patients of SA origin had the questionnaires read aloud.…”

The social difficulties of cancer patients of South Asian Indian and Pakistani origin: a cross-sectional questionnaire and interview study

“…One systematic and cost effective approach may be to introduce a screening questionnaire. We have developed and evaluated the Social Difficulties Inventory (SDI-21), a 21-item questionnaire covering issues of common concern to cancer patients 7–10. In addition, we have investigated the roles and responsibilities of staff and patients in relation to the detection of and support for social difficulties and from this developed guidance on the assessment and management of social difficulties 11.…”