This article discusses the risks of standardization and ipsatization in longitudinal studies. First, it summarizes some common purposes of standardization in psychological studies. Second, it explains why and when standardization and ipsatization are problematic in the analysis of longitudinal data and profiles. Third, it shows alternative ways to achieve similar purposes while avoiding the risks.

The application of mixture models to flexibly estimate linear and nonlinear effects in the SEM framework has received increasing attention (e.g., Jedidi et al., 1997b; Bauer, 2005; Muthén and Asparouhov, 2009; Wall et al., 2012; Kelava and Brandt, 2014; Muthén and Asparouhov, 2014). The advantage of mixture models is that unobserved subgroups with class-specific relationships can be extracted (...

Additive manufacturing (AM) has the potential to create geometrically complex parts that require a high degree of customization, using less material and producing less waste. Recent studies have shown that AM can be an economically viable option for use by the industry, yet there are some inherent challenges associated with AM for wider acceptance. The lack of standards in AM impedes its use fo...

Clinical photography in the field of oculoplastic surgery has many applications. It is possible for clinicians to obtain standardized clinical photographs without a studio. A clinician photographer has the advantage of knowing exactly what to photograph as well as having immediate access to the images. In order to maintain standardization in the photographs, the photographic settings should rem...

The Computational Modeling in Biology Network (COMBINE) is a consortium of groups involved in the development of open community standards and formats used in computational modeling in biology. COMBINE's aim is to act as a coordinator, facilitator, and resource for different standardization efforts whose domains of use cover related areas of the computational biology space. In this perspective a...

Variation, long accepted to be the norm in otolaryngologic surgical practice, has recently come under scrutinization. Efforts can be seen daily in the operating room to standardize procedures with time-outs, checklists, and protocols. The thought is that by enforcing repetition and eliminating variation, it is possible to decrease human error and reduce cost. However, there is understandable re...

Performing a digital forensic investigation (DFI) requires a standardized and formalized process. There is currently neither an international standard nor does a global, harmonized DFI process (DFIP) exist. The authors studied existing state-of-the-art DFIP models and concluded that there are significant disparities pertaining to the number of processes, the scope, the hierarchical levels, and ...

Chemical variability of propolis is discussed with respect to the problem of standardization. Several chemical types of propolis are formulated, based on their plant source. Reliable criteria for chemical standardization of different propolis types are needed but such generally accepted criteria do not yet exist. The chemical profile of "poplar" propolis, typical for the temperate zone, can be ...

BACKGROUND The Canadian Health Measures Survey (CHMS) is an ongoing cross-sectional national survey that includes a measure of 25-hydroxyvitamin D [25(OH)D] by immunoassay. For cycles 1 and 2, the collection period occurred approximately every 2 y, with a new sample of ∼5600 individuals. OBJECTIVE The goal was to standardize the original 25(OH)D CHMS values in cycles 1 and 2 to the internatio...

This paper examines the effect of choice architecture on Massachusetts' Health Insurance Exchange. A policy change standardized cost-sharing parameters of plans across insurers and altered information presentation. Post-change, consumers chose more generous plans and different brands, but were not more price-sensitive. We use a discrete choice model that allows the policy to affect how attribut...