Background: The disappearance of a significant person is an ambiguous loss due to the persistent uncertainty about the whereabouts of the person. Measures specifically capturing the psychological consequences of ambiguous loss are lacking. Therefore, this study aimed to develop the Ambiguous Loss Inventory Plus (ALI+) and evaluated its suitability for use with relatives of missing persons.
Methods: ALI+ items were generated based on established measures for prolonged grief symptoms and literature on psychological responses to ambiguous loss. Eight relatives of missing persons (three refugees, five non-refugees) and seven international experts on ambiguous loss rated all items in terms of understandability and relevance on a scale from 1 (not at all) to 5 (very well).
Results: On average, the comprehensibility of the items was rated as high (all items ≥ 3.7). Likewise, all items were rated as relevant for the assessment of common responses to the disappearance of a loved one. Only minor changes were made to the wording of the items based on the experts' feedback.
Conclusions: These descriptive results indicate that the ALI+ seems to cover the intended concept, thus showing promising face and content validity. However, further psychometric evaluations of the ALI+ are needed.
Keywords: ambiguous loss; disappearance; grief; loss; missing persons; stress.