Ratio index variables or ANCOVA? Fisher's cats revisited.

Pharm Stat

Biostatistics Unit, Centre for Epidemiology and Biostatistics, University of Leeds, Leeds, UK.

Published: October 2010

Over 60 years ago Ronald Fisher demonstrated a number of potential pitfalls with statistical analyses using ratio variables. Nonetheless, these pitfalls are largely overlooked in contemporary clinical and epidemiological research, which routinely uses ratio variables in statistical analyses. This article aims to demonstrate how very different findings can be generated as a result of less than perfect correlations among the data used to generate ratio variables. These imperfect correlations result from measurement error and random biological variation. While the former can often be reduced by improvements in measurement, random biological variation is difficult to estimate and eliminate in observational studies. Moreover, wherever the underlying biological relationships among epidemiological variables are unclear, and hence the choice of statistical model is also unclear, the different findings generated by different analytical strategies can lead to contradictory conclusions. Caution is therefore required when interpreting analyses of ratio variables whenever the underlying biological relationships among the variables involved are unspecified or unclear.

Download full-text PDF

Source
http://dx.doi.org/10.1002/pst.377DOI Listing

Publication Analysis

Top Keywords

ratio variables
20
statistical analyses
8
analyses ratio
8
findings generated
8
random biological
8
biological variation
8
underlying biological
8
biological relationships
8
variables
6
ratio
5

Similar Publications

Background: Risk prediction tools for acutely ill children have been developed in high- and low-income settings, but few are validated or incorporated into clinical guidelines. We aimed to assess the performance of existing paediatric early warning scores for use in low- and middle-income countries using clinical data from a recent large multi-country study in Africa and South-Asia.

Methods: We used data (children across three nutritional strata) from the Childhood Acute Illness and Nutrition (CHAIN) Network cohort study (n = 3101).

View Article and Find Full Text PDF

Background: Orthohantaviruses (also known as hantaviruses) are pathogens, primarily transmitted by rodents, that can cause hemorrhagic fever with renal syndrome (HFRS). In endemic regions of Kazakhstan, no confirmed HFRS cases were detected between 2020 and 2022 raising concerns about detection. Estimate antibody seroprevalence for hantaviruses and identify associated risk factors among high-risk adults in western Kazakhstan in 2023.

View Article and Find Full Text PDF

Objective: We report post hoc analyses of efficacy with first-line avelumab plus axitinib or sunitinib according to baseline neutrophil-to-eosinophil ratio (NER) in patients with advanced renal cell carcinoma (aRCC) from the JAVELIN Renal 101 phase 3 trial.

Methods And Analysis: Progression-free survival (PFS), overall survival (OS) and objective response per baseline NER were analysed in the overall population and in patients with programmed death ligand 1 (PD-L1+) tumours. Multivariable Cox regression analyses to assess the effect of NER after adjustment for other baseline variables were conducted.

View Article and Find Full Text PDF

In this study, the specific capacitance characteristics of a carbon nanotube (CNT) supercapacitor was predicted using different machine learning algorithms, such as artificial neural network (ANN), random forest regression (RFR), -nearest neighbors regression (KNN), and decision tree regression (DTR), based on experimental studies. The results of the simulation verified the accuracy of the ANN algorithm with respect to the data derived from the specific capacitance of the supercapacitor module. It was observed that there was a strong correlation between the experimental results and the predictions made by the ANN algorithm.

View Article and Find Full Text PDF

Background: Anterior shoulder instability with glenoid bone loss presents a challenge in orthopedic surgery. The Latarjet and iliac crest bone graft transfer (ICBGT) procedures are commonly employed for its management, but direct comparative evidence is insufficient.

Methods: Following PRISMA guidelines, a comprehensive search of PubMed, EMBASE, Cochrane Library, and Web of Science was conducted.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!