The Influence of Sample Size on Parameter Estimates in Three-Level Random-Effects Models

Kerkhoff, Denise; Nußbeck, Fridtjof W.

doi:10.3389/fpsyg.2019.01067

Cited by 47 publications

(37 citation statements)

References 43 publications

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“…To investigate the influence of different measurement frequencies (1, 2, 3 or 4 days between each measurement), the parameter estimation bias (peb) [42] was calculated to assess the accuracy of each parameter:…”

Section: Accuracy and Precisionmentioning

confidence: 99%

The initial engraftment of tumor cells is critical for the future growth pattern: a mathematical study based on simulations and animal experiments

et al. 2020

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Background: Xenograft mouse tumor models are used to study mechanisms of tumor growth and metastasis formation and to investigate the efficacy of different therapeutic interventions. After injection the engrafted cells form a local tumor nodule. Following an initial lag period of several days, the size of the tumor is measured periodically throughout the experiment using calipers. This method of determining tumor size is error prone because the measurement is two-dimensional (calipers do not measure tumor depth). Primary tumor growth can be described mathematically by suitable growth functions, the choice of which is not always obvious. Growth parameters provide information on tumor growth and are determined by applying nonlinear curve fitting. Methods: We used self-generated synthetic data including random measurement errors to research the accuracy of parameter estimation based on caliper measured tumor data. Fit metrics were investigated to identify the most appropriate growth function for a given synthetic dataset. We studied the effects of measuring tumor size at different frequencies on the accuracy and precision of the estimated parameters. For curve fitting with fixed initial tumor volume, we varied this fixed initial volume during the fitting process to investigate the effect on the resulting estimated parameters. We determined the number of surviving engrafted tumor cells after injection using ex vivo bioluminescence imaging, to demonstrate the effect on experiments of incorrect assumptions about the initial tumor volume. Results: To select a suitable growth function, measurement data from at least 15 animals should be considered. Tumor volume should be measured at least every three days to estimate accurate growth parameters. Daily measurement of the tumor volume is the most accurate way to improve long-term predictability of tumor growth. The initial tumor volume needs to have a fixed value in order to achieve meaningful results. An incorrect value for the initial tumor volume leads to large deviations in the resulting growth parameters.

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Section: Accuracy and Precisionmentioning

confidence: 99%

The initial engraftment of tumor cells is critical for the future growth pattern: a mathematical study based on simulations and animal experiments

et al. 2020

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“…Mediation analyses were not estimated in the current study because of the strict assumptions underlying causal mediation analyses with only two time points (due to the lack of temporal dissociation; Cole and Maxwell, 2003 ), especially in the context of the low power of the sample size to detect mediation effects. For inferential analyses, missing data was accounted for using a full information maximum likelihood (FIML) approach to missingness (Kerkhoff and Nussbeck, 2019 ). All analyses retained the two participants who reported “Other” gender, but we also examined whether removing these participants influenced any results.…”

Section: Methodsmentioning

confidence: 99%

An Emotion Regulation and Impulse Control (ERIC) Intervention for Vulnerable Young People: A Multi-Sectoral Pilot Study

et al. 2021

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Objective: There is a demonstrated link between the mental health and substance use comorbidities experienced by young adults, however the vast majority of psychological interventions are disorder specific. Novel psychological approaches that adequately acknowledge the psychosocial complexity and transdiagnostic needs of vulnerable young people are urgently needed. A modular skills-based program for emotion regulation and impulse control (ERIC) addresses this gap. The current one armed open trial was designed to evaluate the impact that 12 weeks exposure to ERIC alongside usual care had on young people's ability to regulate emotions, as well as examine potential moderating mechanisms.Methods: Seventy nine young people (50.6% male; M = 19.30; SD = 2.94) were enrolled to the 12 week intervention period. Twenty one practitioners from youth and community health services delivered relevant ERIC modules adjunct to usual care. Linear mixed effects regression (with random intercept) was used to examine change over time across the primary outcome of emotion dysregulation and secondary outcomes of depression, anxiety, stress, experiential avoidance and mindfulness. Moderation analyses were conducted to test whether the magnitude of change in emotion dysregulation moderated change over time in secondary outcomes.Results: Analyses revealed significant improvement in the primary outcome of emotion dysregulation with a moderate effect size (Mean Change = −10.24, 95% CI (−14.41, −6.06; Cohen's dav = −0.53), in addition to decreases in the secondary outcomes of depression, anxiety, stress and experiential avoidance. No improvements in mindfulness were reported. Moderation analyses revealed that the residualised change over time in emotion dysregulation moderated the change over time in symptoms of distress, depression, anxiety, stress, experiential avoidance, and mindfulness.Conclusion: Reductions in the severity of emotion dysregulation, depression, anxiety, stress and experiential avoidance are promising, and were evident despite the complexity of the participants and the diversity of the service setting. The improvements found in each outcome were only observed for those young people whose emotion regulation also improved, providing preliminary evidence for the role of emotion regulation as a key treatment target in this population.

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“…Thus, we determined to treat those variables as interaction variables for turning their effects into non-linear. The treatment made the model more complex and require a larger sample size for sound estimation [58]. Nevertheless, the Markov Chain Monte Carlo method integrating the Bayesian analysis generates a large number of parameters' samples through stochastic processes of Markov chains, which helps fit complex models effectively.…”

Section: Methods and Validationmentioning

confidence: 99%

Escaping from air pollution: The psychological process of domestic migration intention among urban people

Vuong¹,

Le²,

Quang-Loc³

et al. 2021

Preprint

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Rapid urbanization with poor city planning has resulted in severe air pollution in low- and middle-income countries’ urban areas. Given the adverse impacts of air pollution, many responses have been taken, including migration to another city. The current study explores the psychological process and demographic predictors of migration intention among urban people in Hanoi, Vietnam – one of the most polluted capital cities in the world. The Bayesian Mindsponge Framework (BMF) was used to construct the model and perform Bayesian analysis on a stratified random sampling dataset of 475 urban people. We found that the migration intention was negatively associated with the individual’s satisfaction with air quality. The association was moderated by the perceived availability of a better alternative (or nearby city with better air quality). However, the high migration cost due to geographical distance affected the perceived availability of a better alternative negligible. Moreover, it was also found that male and young people were more likely to migrate, but the brain drain hypothesis was not validated. The results hint that without air pollution mitigation measures, the dislocation of economic forces might occur and hinder sustainable urban development. Therefore, collaborative actions among levels of government, with the semi-conducting principle at heart, are recommended to reduce air pollution.

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The Influence of Sample Size on Parameter Estimates in Three-Level Random-Effects Models

Cited by 47 publications

References 43 publications

The initial engraftment of tumor cells is critical for the future growth pattern: a mathematical study based on simulations and animal experiments

The initial engraftment of tumor cells is critical for the future growth pattern: a mathematical study based on simulations and animal experiments

An Emotion Regulation and Impulse Control (ERIC) Intervention for Vulnerable Young People: A Multi-Sectoral Pilot Study

Escaping from air pollution: The psychological process of domestic migration intention among urban people

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