Challenges Related to Assessing Posttraumatic Stress Symptoms in Children and Adolescents: A Generalizability Theory Study

Review Article

Austin J Psychiatry Behav Sci. 2015; 2(3): 1043.

Challenges Related to Assessing Posttraumatic Stress Symptoms in Children and Adolescents: A Generalizability Theory Study

Hukkelberg SS1,2 and Hagtvet KA²

¹Norwegian Centre for Violence and Traumatic Stress Studies (NKVTS), The Norwegian Center for Child Behavioral Development2 Oslo, Norway

²Department of Psychology, University of Oslo, Norway

*Corresponding author: Silje S Hukkelberg, Norwegian Centre for Violence and Traumatic Stress Studies and Department of Psychology, The Norwegian Center for Child Behavioral Development and University of Oslo, Postbox 7053 Majorstuen O306 Oslo, Norway

Received: September 19, 2015; Accepted: December 18, 2015; Published: December 22, 2015


The aims of the study were: 1) To assess different sources of variation of posttraumatic stress symptoms, and 2) to estimate the generalizability of symptom scores in a multi-facet assessment situation by taking into account different sources of measurement error. The Child PTSD Symptom Scale was administered to a clinical sample of 301 children and adolescents age 10 to 18 who had experienced one or more traumatic events. The facets of observation included raters, clinics, items, and traumatic symptoms clusters. Two perspectives on the conceptualization of the PTSD symptoms were applied. Estimated G-study variance and covariance components did not support the differentiation between the three à priori defined clusters re-experiencing, avoidance, and hyper arousal. The D-study results showed acceptable generalizability and dependability coefficients.

Keywords: Posttraumatic stress symptoms; children; Generalizability theory; Multi-facet assessment; Different conceptualizations of PTSD


The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) (American Psychiatric Association, 2000) denotes three clusters of Posttraumatic Stress Symptoms (PTSS) [1] across children and adults based on 17 symptom items: re-experiencing (e.g., through nightmares and intrusive thoughts), avoidance (e.g., situations important for the trauma), and hyper arousal (e.g., concentration problems). These categories of Posttraumatic Stress Disorder (PTSD), as well as their affiliated indicators, have gradually been selected and differentiated into the current 17 items since the diagnosis of PTSD was formally recognized in 1980. Both exploratory and confirmatory factor studies have provided support for this tripartite model in children and adolescents [2-5], although it’s superiority compared to other factor models remains an issue of debate [3,6-8].

As a consequence of the lack of consensus on how PTSS is structured in children and adolescents specifically, most measurement studies focus on the dimensionality and the stability in symptom items. However, this research does not take into account the complex measurement situation that often is associated with assessments of PTSS. A comprehensive assessment of children and adolescents with PTSS often includes collecting data from multiple sources (e.g., raters) and contexts (e.g., clinics) [9]. In order to draw conclusions about the validity of PTSS [10-12]. It is essential that the symptom items show generality across these sources and contexts. However, to our knowledge no studies have actually examined whether PTSS show generality across different contexts. The issue of generality of PTSS in children and adolescents may be especially important, since young people may be more vulnerable to contextual factors in an assessment situation compared to adults. The present study aimed to examine the generality of PTSS in a complex measurement situation. More specifically, a sample of multi-traumatized children and adolescents where assessed for PTSS, assumed to reflect the tripartite DSM-IVdefined symptom categories. The young sample was assessed in seven different clinics by two different raters. Measurement error, or error of generalization, is associated with a facet of observation which is defined as a “… a set of similar conditions of measurement” [13]. In the present study, error of measurement is associated with the facets of items, raters, and clinics, respectively. By applying Generalizability Theory (GT) it is possible to estimate the amount of variance related to each of these facets of the measurement situation which in turn will provide information for estimating generalizability of PTSS as measured in children and adolescents.

Reliability of posttraumatic stress symptoms scores

Two issues are of importance when considering the generality of a construct [14]. Most commonly, factor structure and reliability are estimated from sample data to be generalized to a population of persons. The present study deals with another type of generalization, that is, to what extent the specific score of a construct can be generalized to a universe of items beyond the items included in the specific inventory [15] that is, generalizing to a content domain of construct relevant items. Further, it may be that factors related to the assessment situation, like clinics, raters, or more idiosyncratic properties of a sample, may influence on how well PTSS scores can be generalized. This type of generalization has, to our knowledge, not yet been considered in the measurement research on PTSS.

The DSM-IV defined categorization of symptom items, as well as other constellations of items, is often found to show acceptable levels of reliability using Cronbach’s alpha [1,7,16,17]. However, is founded on classical test theory which assumes the existence of only one undifferentiated error term. When studies in fact are based on multi- faceted measurement designs, i.e., with several sources of measurement error, it is likely that Cronbach’s coefficient alpha represents an inflated estimate of generalizability because relevant sources of error variation have not been included in the estimation procedure. In light of the upcoming revision of PTSD, an investigation of the reliability of the current tripartite symptom clusters seems warranted. The present study aimed to extend knowledge on reliability of the PTSS indicators in children and adolescents by providing better arguments for the generality of the construct (Figure 1).