Evidence map›Paper›PMID 19341469›Full record

ArticleBMC health services research2009

Is there much variation in variation? Revisiting statistics of small area variation in health services research.

Berta Ibáñez, Julián Librero, Enrique Bernal-Delgado, Salvador Peiró, Beatriz González López-Valcarcel, Natalia Martínez, Felipe Aizpuru

Abstract read
In one paragraph

Article in BMC health services research, 2009. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 39 papers.

0numbers the graph read from it
0cells of the map it votes in
39citing 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

39 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

7 authors.

Berta IbáñezInstituto Aragonés de Ciencias de la Salud, Zaragoza, Spain. ibanez@bioef.org
Julián Librero
Enrique Bernal-Delgado
Salvador Peiró
Beatriz González López-Valcarcel
Natalia Martínez
Felipe Aizpuru

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundThe importance of Small Area Variation Analysis for policy-making contrasts with the scarcity of work on the validity of the statistics used in these studies. Our study aims at 1) determining whether variation in utilization rates between health areas is higher than would be expected by chance, 2) estimating the statistical power of the variation statistics; and 3) evaluating the ability of different statistics to compare the variability among different procedures regardless of their rates.

methodsParametric bootstrap techniques were used to derive the empirical distribution for each statistic under the hypothesis of homogeneity across areas. Non-parametric procedures were used to analyze the empirical distribution for the observed statistics and compare the results in six situations (low/medium/high utilization rates and low/high variability). A small scale simulation study was conducted to assess the capacity of each statistic to discriminate between different scenarios with different degrees of variation.

resultsBootstrap techniques proved to be good at quantifying the difference between the null hypothesis and the variation observed in each situation, and to construct reliable tests and confidence intervals for each of the variation statistics analyzed. Although the good performance of Systematic Component of Variation (SCV), Empirical Bayes (EB) statistic shows better behaviour under the null hypothesis, it is able to detect variability if present, it is not influenced by the procedure rate and it is best able to discriminate between different degrees of heterogeneity.

conclusionThe EB statistics seems to be a good alternative to more conventional statistics used in small-area variation analysis in health service research because of its robustness.

Indexed as

Health Services ResearchSmall-Area AnalysisAmputation, SurgicalAppendectomyArthroplasty, Replacement, KneeConfidence IntervalsHealth PlanningHealth PolicyHernia, InguinalHip FracturesHumansLegPacemaker, ArtificialPractice Patterns, Physicians'Spain

Identifiers

PMID19341469
PMCPMC2676262

What OpenQuestion holds

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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.