Exploratory analyses to improve model fit: Errors due to misspecification and a strategy to reduce their occurrence

Two Lagrange multiplier (LM) methods may be used in specification searches for adding parameters to models: one based on univariate LM tests and respecification of the model (LM‐respecified method) and the other based on a partitioning of multivariate LM tests (LM‐incremental method). These methods may result in extraneous parameters being included in models due to either sampling error or the model being misspecified. A 2‐stage specification search may be used to reduce errors due to misspecification. In the 1st stage, parameters are added to models based on LM tests to maximize fit. Second, parameters added in the 1st stage are deleted if they are no longer necessary to maintain model fit. Illustrations are presented to demonstrate that errors due to misspecification occur with the LM‐respecified method and are even more likely with the LM‐incremental approach. These illustrations also show how the deletion stage can help eliminate some of these errors.     

Difference score reliabilities within the RIAS-2 and WISC-V

Many prominent intelligence tests (e.g., Wechsler Intelligence Scale for Children, Fifth Edition [WISC-V] and Reynolds Intellectual Abilities Scale, Second Edition [RIAS-2]) offer methods for computing subtest- and composite-level difference scores. This study uses data provided in the technical manual of the WISC-V and RIAS-2 to calculate reliability coefficients for difference scores. Subtest-level difference score reliabilities range from 0.59 to 0.99 for the RIAS-2 and from 0.53 to 0.87 for the WISC-V. Composite-level difference score reliabilities generally range from 0.23 to 0.95 for the RIAS-2 and from 0.36 to 0.87 for the WISC-V. Emphasis is placed on comparisons recommended by test publishers and a discussion of minimum requirements for interpretation of differences scores is provided.     

The relationship between inertial measurement unit-derived ‘force signatures’ and ground reaction forces during cricket pace bowling

Abstract

This study assessed the reliability and validity of segment measured accelerations in comparison to front foot contact (FFC) ground reaction force (GRF) during the delivery stride for cricket pace bowlers. Eleven recreational bowlers completed a 30-delivery bowling spell. Trunk- and tibia-mounted inertial measurement units (IMUs) were used to measure accelerations, converted to force, for comparisons to force plate GRF discrete measures. These measures included peak force, impulse and the continuous force–time curve in the vertical and braking (horizontal) planes. Reliability and validity was determined by intra-class correlation coefficients (ICC), coefficient of variation (CV), Bland–Altman plots, paired sample t-tests, Pearson’s correlation and one-dimensional (1D) statistical parametrical mapping (SPM). All ICC (0.90–0.98) and CV (4.23–7.41%) were acceptable, except for tibia-mounted IMU braking peak force (CV = 12.44%) and impulse (CV = 18.17%) and trunk vertical impulse (CV = 17.93%). Bland–Altman plots revealed wide limits of agreement between discrete IMU force signatures and force plate GRF. The 1D SPM outlined numerous significant (p < 0.01) differences between trunk- and tibia-located IMU-derived measures and force plate GRF traces in vertical and braking (horizontal) planes. The trunk- and tibia-mounted IMUs appeared to not represent the GRF experienced during pace bowling FFC when compared to a gold-standard force plate.     

Exploring Dialectical Tensions of Leading Volunteers in Two Community Choirs

Leaders of volunteers face different challenges than leaders of paid employees due to different motivations and reward expectations. After synthesizing previous research applying dialectical theory to group members or leaders, this study examines the dialectical tensions that leaders of volunteers experienced and the communication they used to manage those tensions as reported by both the leaders and the volunteers. A constant-comparison method was used to analyze observations and interviews of members and leaders of two community choirs. The findings suggest that leaders of volunteers face eight dialectical tensions representing three broad categories: (a) task and relationship; (b) process and outcome; and (c) internal and external. Leaders negotiated these dialectical tensions through communication strategies including use of humor and appeals to artistic spirituality. These strategies represent hybridization and dualistic discourse rather than a monologic emphasis of one course of action over another.     

The Interparental Relationship and Family Problem Solving with Preadolescent Males

This study examines associations between the quality of the interparental relationship and how well 68 family triads (mother, father, preadolescent son) solved salient problems which arose at home. Four aspects of the interparental relationship (marital satisfaction, parental agreement, conflict during family problem solving, and parental coalitions) were included in a regression analysis which controlled for family structure and child externalizing. A longitudinal design assessed families when mean child age was 9.7 years and 2 years later. Parental agreement consistently facilitated family problem solving. However, strong parental coalitions inhibited family problem solving, which may be attributed to frustrated autonomy needs of preadolescent males in response to the parental coalition. Stepfamilies had less effective problem solving at Time 1. The results confirm the benefits of parental agreement to child outcomes via enhanced family problem solving but show a reverse effect when agreement occurs in the context of coalitions against a preadolescent son.