Evidence map›Paper›PMID 34510501›Full record

ArticleStatistics in medicine2021

Informing power and sample size calculations when using inverse probability of treatment weighting using the propensity score.

Peter C Austin

Registry-linked trialAbstract read
In one paragraph

Article in Statistics in medicine, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT06945510 (A Multi-center Study to Evaluate the Economic and Clinical Impact of PCT Guided Antibiotics Use in Critically Ill Adult Patients in China.), which is not on this map. Cited by 25 papers.

0numbers the graph read from it
0cells of the map it votes in
25citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT06945510 nanot yet recruitingnot on this mapstarted 2025, after this paper: background citation

A Multi-center Study to Evaluate the Economic and Clinical Impact of PCT Guided Antibiotics Use in Critically Ill Adult Patients in China.

TypeinterventionalSponsorChina-Japan Friendship HospitalRan2025 to 2026Enrolled800ConditionsSepsisArmsPCT detection
3 · Its place in the literature

Who cites it

25 citing papers in PubMed.

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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

1 author.

Peter C AustinICES, Toronto, Ontario, Canada.ORCID 0000-0003-3337-233X

Funding

CIHR PJT 166161
6 · The paper itself

Abstract

Propensity score weighting is increasingly being used in observational studies to estimate the effects of treatments. The use of such weights induces a within-person homogeneity in outcomes that must be accounted for when estimating the variance of the estimated treatment effect. Knowledge of the variance inflation factor (VIF), which describes the extent to which the effective sample size has been reduced by weighting, allows for conducting sample size and power calculations for observational studies that use propensity score weighting. However, estimation of the VIF requires knowledge of the weights, which are only known once the study has been conducted. We describe methods to estimate the VIF based on two characteristics of the observational study: the anticipated prevalence of treatment and the anticipated c-statistic of the propensity score model. We considered five different sets of weights: those for estimating the average treatment effect (ATE), the average treated effect in the treated (ATT), and three recently described sets of weights: overlap weights, matching weights, and entropy weights. The VIF was substantially smaller for the latter three sets of weights than for the first two sets of weights. Once the VIF has been estimated during the design phase of the study, sample size and power calculations can be done using calculations appropriate for a randomized controlled trial with similar prevalence of treatment and similar outcome variable, and then multiplying the requisite sample size by the estimated VIF. Implementation of these methods allows for improving the design and reporting of observational studies that use propensity score weighting.

Indexed as

Propensity ScoreHumansObservational Studies as TopicSample Sizeinverse probability of treatment weightingpowerpropensity scoresample sizestudy design

Identifiers

PMID34510501
PMCPMC9293235

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Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.