https://doi.org/10.1177/0193945920951223 Western Journal of Nursing Research 1–11 © The Author(s) 2020 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/0193945920951223 journals.sagepub.com/home/wjn Original Research Critical illness in a child is a known source of stress to parents. Even more stressful is the admission of a child to a pediatric intensive care unit (PICU). Such an admission is typically unexpected, the child’s condition is precarious, and the overall experience is as stressful (Alzawad et al., 2020). Over 230,000 children are admitted annually to PICUs in the United States (Watson & Hartman, 2014) and post-traumatic stress disorder (PTSD) rates in parents following PICU admission range between 10% and 42% (Yagiela et al., 2019). Evidence revealed that PICU parental stressors were predictive of PTSD symptoms after PICU discharge (Colville et al., 2009; Colville & Gracey, 2006). PTSD symptoms such as emotional avoid- ance, numbing, and dissociative symptoms were even reported in parents during the acute period of their child’s PICU hospi- talization (Alzawad et al., 2020). Yagiela et al. (2019) argued that understanding factors associated with parental stress at the beginning of the PICU admission can guide planning strate- gies to prevent the development of stress-related morbidity. Despite the large numbers of children and parents affected, there is only one scale, the Parental Stressor Scale: Pediatric Intensive Care Unit (PSS:PICU), that measures the potential sources of stress and the impact of environmental stressors in the PICU on parents when their child is admitted to the PICU. Understanding the unique stressors experienced by parents during such an illness crisis is crucial in planning evidence- based and effective interventions for testing in future research. Additionally, understanding parental stressors can help predict who is at risk of developing PTSD, and uncover the best time to intervene in order to help prevent PTSD after PICU discharge. The Need for a Valid Scale in Research and Practice The PSS:PICU was developed over 30 years ago and is the only available questionnaire that measures parent-reported stressors in the PICU (Carter & Miles, 1989; Carter et al., 1985; Miles & Carter, 1982; Miles, Carter, Hennessey, et al., 1989; Miles, Carter, Riddle, et al., 1989; Miles et al., 1984). The conceptual framework that guided the development of the PSS:PICU scale was based on Lazarus’s cognitive-phe- nomenological theory of stress, Selye’s stress theory, Roy’s adaptation model of nursing, Lazarus, and Moos’s theory of coping (Lazarus & Launier, 1978; Moos & Billings, 1982; 951223WJN XX X 10.1177/0193945920951223Western Journal of Nursing ResearchAlzawad et al. research-article 2020 1 University of Iowa, Iowa City, IA, USA 2 University of Washington, Seattle, WA, USA 3 Fred Hutchinson Cancer Research Center, Seattle, WA, USA Corresponding Author: Zainab Alzawad, University of Iowa, 101 College of Nursing Building, 50 Newton Rd, Iowa City, IA, 52242, USA. Email: zainab-alzawad@uiowa.edu Content Validity of Parental Stressor Scale: Pediatric Intensive Care Unit (PSS:PICU) Zainab Alzawad 1 , Frances M. Lewis 2,3 , and Min Li 2 Abstract Around 10% to 42% of parents suffer from post-traumatic stress disorder following child’s Pediatric Intensive Care Unit (PICU) admission. What is needed is an understanding of factors associated with parental stress at the beginning of the PICU admission to guide strategies to prevent the development of stress-related morbidity. Only one measure exists to assess sources of PICU-related parental stress, the Parental Stressor Scale: Pediatric Intensive Care Unit (PSS:PICU). However, this scale has not been modified in over 30 years. The purpose of this study is to examine the content validity and descriptive statistics of the PSS:PICU, propose initial refinements of the scale based on interviews and quantitative analyses, and identify threats to validity in this measure using a convergent parallel mixed methods design. Three validity threats were identified: construct underrepresentation, construct-irrelevant variance, and item redundancy. Suggested scale refinements were to delete 17, revise 7, retain 15, and add 16 items for future testing. Keywords PICU, parental stressor, content validity, instrument revision, mixed methods