Likert scales are routinely used in educational and psychological research as measures of constructs of interest. If sound scale development procedures are followed, the resulting scale can reliably and validly measure a construct. However, if a given scale is used to make comparisons among different populations of respondents (e.g., cultures; Riordan & Vandenberg, 1994), over time in longitudi...

Using male/female and Caucasian/African American comparison groups, this study examined the practical ramifications of using two IRT-based analytic methods, DFIT and the Likelihood Ratio Test (LRT), in assessing the measurement invariance of a 21-item leadership development scale under ten sample size conditions (e.g., 200, 500, & 1000). In nine of ten conditions, the LRT identified multiple it...

Likert scales are routinely used in educational and psychological research as measures of constructs of interest. If sound scale development procedures are followed, the resulting scale can reliably and validly measure a construct. However, if a given scale is used to make comparisons among different populations of respondents (e.g., cultures; Riordan & Vandenberg, 1994), over time in longitudi...

This study uses simulated data to compare two methods of calculating Differential Test Functioning (DTF): Raju’s DFIT, a parametric method that measures the squared difference between two Test Characteristic Curves (Raju, van der Linden & Fleer, 1995), and a variance estimator based on the Mantel-Haenszel/Liu-Agresti method, a non-parametric method enabled in the DIFAS (Penfield, 2005) program....

Multistage hydraulic fracturing is a technique to extract hydrocarbon from tight and unconventional reservoirs. Although big advancements occurred in this field, understanding of the created fractures location, size, complexity, proppant distribution its infancy. This study provides recent advances methods techniques used diagnose formations. These include tracer flowback analysis, fiber optics...

The effectiveness of confirmatory factor analytic (CFA) and item response theory (IRT) methods of assessing measurement invariance were investigated using simulated data with a known lack of invariance. Across all study conditions, IRT likelihood ratio (LR) tests consistently outperformed both CFA and IRT differential functioning of items and tests (DFIT) analyses in terms of detecting a lack o...

There have been various methods created based on the regression ideas to resolve the problem of data set containing censored observations, i.e. the Buckley-James method, Miller’s method, Cox method, and Koul-Susarla-Van Ryzin estimators. Even though comparison studies show the Buckley-James method performs better than some other methods, it is still rarely used by researchers mainly because of ...

Despite the extensive implementation of multiple drug therapy (MDT) in most leprosy-endemic countries world-wide since 1982, bringing about a remarkable reduction in prevalence, there are still regions at the sub-national level where the implementation of MDT remains difficult. The state of Bihar (population 86.3 million) in India is a good example of such a region. Previously rated as one of t...

The diagnostic fracture injection test (DFIT) is widely used to obtain the closure pressure, reservoir permeability, and pressure. Conventional methods for analyzing DFIT are based on assumption that a vertical well drilled in ultra-low permeability reservoirs with potential multiple closures but fails consider horizontal wells. There still significant debate about rigorousness validity of thes...

Correct estimation of hydraulic fracture height growth is a critical step in the design Hydraulic Fracturing (HF) treatment, as it maximizes reservoir stimulation and returns on investment. The fractures governed by several situ conditions, especially stress variation with depth. common workflow to estimate building mechanical earth model (MEM) calibrating using Diagnostic Fracture Injection Te...