Purpose – The purpose of this paper is to examine organizational identification as an underlying mechanism for how perceptions of interpersonal leadership are related to employee engagement, and its relationship with commitment and job tension. Design/methodology/approach – A sample of 451 full-time employees at an international firm completed a web-based survey. Findings – Organizational identification mediated the relationship between perceived interpersonal leadership and engagement, which mediated the relationship between perceived interpersonal leadership and commitment. Engagement mediated the relationship between identification and job tension. Research limitations/implications – Limitations include cross-sectional data. Strengths include a large field sample. Implication is that leaders who encourage employees’ identification with the organization may also encourage their engagement. Practical implications – Interpersonal leadership characteristics can be developed, and are positively related to employees’ identification, commitment, and engagement, which are negatively related to job tension. Social implications – Interpersonal leaders are positively associated with employees’ engagement; high engagement has been related to positive employee health and well-being. A healthy workforce translates into a healthy society. Originality/value – This study is one of the few to examine the underlying mechanisms through which leadership relates to engagement.

The majority of mild cognitive impairment (MCI) studies use baseline and one follow-up measurement to determine the clinical course of the disorder. This report of MCI clinical course is based on the a statistical evaluation of multiple neurocognitive tests over a 60 month period in elderly normal and MCI cohorts. The data includes serial informant-based measures (Clinical Dementia Rating [CDR]) and a comprehensive battery of neuropsychological tests analyzed by two different regression methods. Twenty-nine elderly participants entered the study as neurocognitively normal; 26 remained normal, 2 progressed to MCI, and 1 progressed to dementia. Eighty-three participants entered the study as multiple domain MCI cases; 10 became normal, 46 remained MCI, and 27 progressed to dementia. Three of the 27 demented died with full necropsies performed (one case was progressive supranuclear palsy and two confirmed Alzheimer’s disease with severe cerebral amyloid angiopathy (CAA)). Without serial measures, 1 in 8 MCI could be misclassified as “stable MCI” despite reverting to normal. The stable MCI cohorts did not benefit from practice effects though the normal subjects did. Applying Classification and Regression Tree (CART) analysis enabled prediction of the endpoint status of participants from baseline values with 78.6% accuracy. The fluctuating cognitive status of the multiple domain MCI cases implies a remitting pathologic process with elements of recovery consistent with a progressive microvasculopathy such as CAA.

In this 3-Study article, the authors present an abridged version of Colquitt's (2001) 20-item measure of organizational justice. In Study 1, using a sample of 278 undergraduate students, they applied a systematic scale-reduction technique to determine which items should remain in the abridged scale. In Study 2 and 3, using two separate field samples (N = 173, N = 517; respectively) they provide construct, convergent, and discriminant validity evidence in support of the abridged scale. Their results provide evidence that the abridged version of Colquitt's measure maintains the psychometric quality of the original full scale and, therefore, can be used in its place.

Sahara Mustard (Brassica tournefortii; hereafter mustard), an exotic plant species, has invaded habitats throughout the arid southwestern United States. Mustard has reached high densities across aeolian sand habitats of southwestern deserts, including five distinct sand habitats in the eastern Coachella Valley, California. We examined trends in ground-dwelling arthropod community structure concurrent with mustard invasion in 90 plots within those habitats from 2003 to 2011 (n = 773 plotÁyears). We expected arthropod communities to respond negatively to mustard invasion because previous work documented significant negative impacts of mustard on diversity and biomass of native plants, the primary resource base for many of the arthropods. Arthropod abundance and species richness declined during the study period while mustard cover increased, and arthropod metrics were negatively related to mustard cover across all plots. When controlling for non-target environmental correlates (e.g. perennial frequency and precipitation) and for potential factors that we suspected of mediating mustard effects (e.g. native cover and sand compaction), negative relationships with mustard remained statistically supported. Nevertheless, arthropod richness's relationship decreased slightly in strength and significance suggesting that mechanistic pathways may be both direct (via habitat structure) and indirect (via native cover suppression and sand compaction). However, mechanistic pathways for mustard effects, particularly on arthropod abundance, remain unclear. Most arthropod taxa, including most detritivores, decreased through time and were negatively related to mustard cover. In contrast, many predators were positively related to mustard. In total, our study provides substantial evidence for a negative effect of Sahara mustard on the structure of a ground-dwelling arthropod community.

We propose a chi-square goodness-of-fit test for autoregressive logistic regression models. General guidelines for a two-dimensional binning strategy are provided, which make use of two types of maximum likelihood parameter estimates. For smaller sample sizes, a bootstrap p-value procedure is discussed. Simulation studies indicate that the test procedure satisfactorily approximates the correct size and has good power for detecting model misspecification. In particular, the test is very good at detecting the need for an additional lag. An application to a dataset relating to screening patients for late-onset Alzheimer's disease is provided.