Many of the CROPS studies have been conducted in other countries including in Bosnia, Germany, and the Netherlands. The majority were conducted with community samples recruited from schools. One study (Greenwald et al., 2001) examined the psychometrics in a juvenile justice population.
CROPS scores have been found to correlate with TSCC (r=.70) and Adolescent Dissociative Experiences Survey scores (r=.74). The CROPS also correlates in the expected direction with measures of distress, family stress, neuroticism, and mastery, and with the degree of trauma a child had experienced. (Greenwald & Rubin, 1999; Greenwald et al., 2001).
Changes in CROPS scores correlate with change in TSCC scores (r=.70; Greenwald et al., 2001).
An exploratory principal components factor analysis with an oblique rotation suggested a three-factor structure, based on the scree test. The first factor contained a wide-range of items including self-alienation and dysphoria. The second contained somatic symptoms, and the third contained items associated with avoidance and intrusive thoughts. A second-order factor analysis suggested that each scale could be conceptualized within the single overarching construct of post-traumatic symptoms.
In a study of 15 sexually abused Iranian girls randomly assigned to CBT or EMDR treatment, the CROPS showed evidence of sensitivity to intervention effects, with pre- to post-test comparisons showing significant improvement for the EMDR group but not the CBT group (Jaberghaderi, Greenwald, Rubin, Zand, & Dolatabadi, 2004).
The PROPS and CROPS were also used in a randomized trial of 29 boys with conduct problems. Boys were randomly assigned to standard care (residential or day treatment) or standard care plus 3 trauma-focused EMDR sessions. No significant treatment differences were found with the CROPS or PROPS. Both groups decreased on the Impact of Events Scale, 8-item version (IES-8), with a trend favoring the treatment group. The authors suggested the difference in findings between the IES-8 and CROPS/PROPS may be because the IES-8 focused on a specific traumatic memory, which was the target of treatment, whereas the CROPS and PROPS are more broad-spectrum trauma measures (Soberman, Greenwald, & Rule, 2002).
The CROPS was used in a study examining the effects of indirect exposure to the 9/11 attacks (Saylor, Cowart, Lipovsky, Jackson, & Finch, 2003). PROPS scores and scores on the Pediatric Emotional Distress Scale (another parentreport measure) were related to exposure to negative and positive media images, but CROPS scores were not.