Problems with Rationales for Parceling that Fail to Consider Parcel-Allocation Variability

In structural equation modeling applications, parcels—averages or sums of subsets of item scores—are often used as indicators of latent constructs. Parcel-allocation variability (PAV) is variability in results that arises within sample across alternative item-to-parcel allocations. PAV can manifest in all results of a parcel-level model (e.g., model fit, parameter estimates, standard errors, and inferential decisions). It is a source of uncertainty in parcel-level model results that can be investigated, reported, and accounted for. Failing to do so raises representativeness and replicability concerns. However, in recent methodological literature (Cole, Perkins, &; Zelkowitz, 2016 Cole, D. A., Perkins, C. E., &; Zelkowitz, R. L. (2016). Impact of homogeneous and heterogeneous parceling strategies when latent variables represent multidimensional constructs. Psychological Methods, 21(2), 164–174. doi: 10.1037/met0000047[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Little, Rhemtulla, Gibson, &; Shoemann, 2013 Little, T. D., Rhemtulla, M., Gibson, K., &; Schoemann, A. M. (2013). Why the items versus parcels controversy needn't be one. Psychological Methods, 18(3), 285–300. doi: 10.1037/a0033266[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Marsh, Ludtke, Nagengast, Morin, &; von Davier, 2013 Marsh, H. W., Lüdtke, O., Nagengast, B., Morin, A., &; von Davier, M. (2013). Why item parcels are (almost) never appropriate: Two wrongs do not make a right—camouflaging misspecification with item parcels in CFA models. Psychological Methods, 18(3), 257–284. doi: 10.1037/a0032773[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Rhemtulla, 2016 Rhemtulla, M. (2016). Population performance of SEM parceling strategies under measurement and structural model misspecification. Psychological Methods, 21(3), 348–368. doi: 10.1037/met0000072[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) parceling has been justified and recommended in several situations without quantifying or accounting for PAV. In this article, we explain and demonstrate problems with these rationales. Overall, we find that: (1) using a purposive parceling algorithm for a multidimensional construct does not avoid PAV; (2) passing a test of unidimensionality of the item-level model need not avoid PAV; and (3) a desire to improve power for detecting structural misspecification does not warrant parceling without addressing PAV; we show how to simultaneously avoid PAV and obtain even higher power by comparing item-level models differing in structural constraints. Implications for practice are discussed.     

Does Reintegration Stress Contribute to Suicidal Ideation Among Returning Veterans Seeking PTSD Treatment?

Although posttraumatic stress disorder (PTSD) and other psychiatric symptoms are well‐established risk factors for suicidal ideation among returning veterans, less attention has been paid to whether the stress of reintegrating into civilian society contributes to suicidal ideation. Utilizing a sample of 232 returning veterans (95% male, mean age = 33.63 years) seeking PTSD treatment, this study tested whether reintegration difficulties contribute to suicidal ideation over and above the influence of PTSD symptoms, depression symptoms, and potential substance misuse. Logistic regressions indicated that reintegration stress had a unique effect on suicidal ideation over and above PTSD and depression symptoms. Reintegration stress interacted with substance misuse to predict suicidal ideation, such that the effect of reintegration stress on suicidal ideation was much larger for those with potential substance misuse. Exploratory analyses also examined which types of reintegration difficulties were associated with suicidal ideation, and found that difficulty maintaining military friendships, difficulty getting along with relatives, difficulty feeling like you belong in civilian society, and difficulty finding meaning/purpose in life were all significantly associated with suicidal ideation, beyond the effects of psychiatric symptoms and potential substance misuse. Findings highlight the importance of addressing reintegration stress for the prevention of suicide among returning veterans. Implications for treatment are discussed.