Measurement invariance,the lack thereof,and modeling change

Purpose

Measurement invariance issues should be considered during test construction. In this paper, we provide a conceptual overview of measurement invariance and describe how the concept is implemented in several different statistical approaches. Typical applications look for invariance over things such as mode of administration (paper and pencil vs. computer based), language/translation, age, time, and gender, to cite just a few examples. To the extent that the relationships between items and constructs are stable/invariant, we can be more confident in score interpretations.

Methods

A series of simulated examples are reported which highlight different kinds of non-invariance, the impact it can have, and the effect of appropriately modeling a lack of invariance. One example focuses on the longitudinal context, where measurement invariance is critical to understanding trends over time. Software syntax is provided to help researchers apply these models with their own data.

Results

The simulation studies demonstrate the negative impact an erroneous assumption of invariance may have on scores and substantive conclusions drawn from naively analyzing those scores.

Conclusions

Measurement invariance implies that the links between the items and the construct of interest are invariant over some domain, grouping, or classification. Examining a new or existing test for measurement invariance should be part of any test construction/implementation plan. In addition to reviewing implications of the simulation study results, we also provide a discussion of the limitations of current approaches and areas in need of additional research.

     

Field Survey and Comparative Study of Pteris Vittata and Pityrogramma Calomelanos Grown on Arsenic Contaminated Lands with Different Soil pH

Bulletin of Environmental Contamination and Toxicology - In field survey, Pteris vittata and Pityrogramma calomelanos were only found in arsenic (As) contaminated areas with soil pH 7.2–8.8...     

Development and Feasibility of a Community-Based,Culturally Flexible Colorectal Cancer Prevention Program

Comprehensive cancer centers are an important community resource for cancer prevention education in their catchment areas. Colorectal cancer remains one of the most commonly diagnosed cancers in the United States, making prevention a priority. Colorectal cancer prevention targets include lifestyle modifications that are influenced by cultural norms, such as diet change, physical activity and screening behavior. Cancer centers must tailor prevention efforts to multiethnic catchment areas. This paper describes the development and feasibility of a comprehensive cancer center’s approach to community-based colorectal cancer prevention in Houston, Texas, specifically targeting Hispanic and Asian populations. Sites were recruited through a city-wide network of partnerships between the community relations department in the hospital and community organizations. The program consisted of three workshop-style classes per community site. Each class had a similar overall structure, but cultural and site-specific adaptations were made for each group. A total of 33 classes were taught at nine distinct community sites to 1054 participants over 9 months. This program structure may be adapted for the future dissemination of other cancer prevention tools to communities in the area.     

Use of Evidence-Based Interventions and Implementation Strategies to Increase Colorectal Cancer Screening in Federally Qualified Health Centers

While colorectal cancer (CRC) screening rates have been increasing in the general population, rates are considerably lower in Federally Qualified Health Centers (FQHCs), which serve a large proportion of uninsured and medically vulnerable patients. Efforts to screen eligible patients must be accelerated if we are to reach the national screening goal of 80% by 2018 and beyond. To inform this work, we conducted a survey of key informants at FQHCs in eight states to determine which evidence-based interventions (EBIs) to promote CRC screening are currently being used, and which implementation strategies are being employed to ensure that the interventions are executed as intended. One hundred and forty-eight FQHCs were invited to participate in the study, and 56 completed surveys were received for a response rate of 38%. Results demonstrated that provider reminder and recall systems were the most commonly used EBIs (44.6%) while the most commonly used implementation strategy was the identification of barriers (84.0%). The mean number of EBIs that were fully implemented at the centers was 2.4 (range 0–7) out of seven. Almost one-quarter of respondents indicated that their FQHCs were not using any EBIs to increase CRC screening. Full implementation of EBIs was correlated with higher CRC screening rates. These findings identify gaps as well as the preferences and needs of FQHCs in selecting and implementing EBIs for CRC screening.