Evidence map›Paper›PMID 40924352›Full record

ArticleJournal of behavioral medicine2026

Determining the power of a 1-sided z-test given only the power of the corresponding 2-sided test.

Amy Liang, Kristopher J Preacher, Nathaniel J Williams, Paul D Allison, Steven C Marcus, Sonya K Sterba

Abstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in Journal of behavioral medicine, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing 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.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
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

6 authors.

Amy LiangDepartment of Psychology and Human Development, Vanderbilt University, 230 Appleton Place, Nashville, TN, 37203‑5721, USA.
Kristopher J PreacherDepartment of Psychology and Human Development, Vanderbilt University, 230 Appleton Place, Nashville, TN, 37203‑5721, USA. kris.preacher@vanderbilt.edu.ORCID 0000-0003-4099-3636
Nathaniel J WilliamsSchool of Social Work, Boise State University, Boise, ID, USA.
Paul D AllisonStatistical Horizons LLC, P.O. Box 282, Ardmore, PA, 19003, USA.
Steven C MarcusPenn Center for Mental Health, University of Pennsylvania School of Medicine, 3535 Market Street, Philadelphia, PA, 19104, USA.
Sonya K SterbaDepartment of Psychology and Human Development, Vanderbilt University, 230 Appleton Place, Nashville, TN, 37203‑5721, USA.

Funding

Transforming mental health delivery through behavioral economics and implementation scienceP50MH113840 · NIMH · UNIVERSITY OF PENNSYLVANIA · PI BEIDAS, RINAD SARY, BUTTENHEIM, ALISON MEREDITH · 2017 to 2020
$6.6M
NIMH NIH HHS P50 MH113840NIMH NIH HHS P50MH113840
6 · The paper itself

Abstract

Estimating statistical power is essential for designing behavioral medicine studies efficiently and conserving finite resources. Sometimes behavioral medicine researchers are interested in calculating power for 1-sided z-tests of individual parameters (e.g., slopes) in complex models such as multilevel structural equation models or multilevel mixture regression models. For such models, calculating power for 1-sided z-tests is cumbersome because: (a) online z-test power calculator tools are inapplicable, (b) commonly-used power analysis software provides power only for 2-sided z-tests and does not allow changing alpha, and (c) published power tables typically provide power results only for 2-sided z-tests. Hence, here we introduce straightforward and resource-efficient conversion formulas to estimate the power of 1-sided z-tests of individual parameters in any model by using direct power conversions from the corresponding 2-sided tests. We then implement these conversion formulas in accessible R and Excel software. This brief report thus provides behavioral medicine researchers with a convenient and practical solution for power calculation that minimizes the time, financial, and computational resources typically needed for power estimation.

Indexed as

Models, StatisticalResearch DesignData Interpretation, StatisticalHumansSoftwareDirectional and non-directional hypothesesHypothesis testingPower conversionStatistical power

Identifiers

PMID40924352
PMCPMC13253764

What OpenQuestion holds

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LicenceCC BY
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Registered trials

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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.