Evidence map›Paper›PMID 34275447›Full record

ArticleBMC medical research methodology2021

Need of care in interpreting Google Trends-based COVID-19 infodemiological study results: potential risk of false-positivity.

Kenichiro Sato, Tatsuo Mano, Atsushi Iwata, Tatsushi Toda

Abstract read
In one paragraph

Article in BMC medical research methodology, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 23 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
23citing papers in PubMed, 1 pooled it
–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

23 citing papers in PubMed, 1 synthesis or guideline pooled it.

  1. Pooled it
  2. 8. Guard against statistical fallacies in medical research.Journal of postgraduate medicine · 2026
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  5. Observational
  6. The Interest in Betting, Smoking, Alcohol, and Drugs in Malawi: Changing Trends between 2012-2022.Malawi medical journal : the journal of Medical Association of Malawi · 2024
    Article
  7. Article
  8. Article
  9. Article
  10. Article
  11. Forecasting and Surveillance of COVID-19 Spread Using Google Trends: Literature Review.International journal of environmental research and public health · 2022
    Review
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  14. Observational
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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

4 authors.

Kenichiro SatoDepartment of Neurology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. kenisatou-tky@umin.ac.jp.
Tatsuo ManoDepartment of Neurology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
Atsushi IwataDepartment of Neurology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. iwata@m.u-tokyo.ac.jp.
Tatsushi TodaDepartment of Neurology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundGoogle Trends (GT) is being used as an epidemiological tool to study coronavirus disease (COVID-19) by identifying keywords in search trends that are predictive for the COVID-19 epidemiological burden. However, many of the earlier GT-based studies include potential statistical fallacies by measuring the correlation between non-stationary time sequences without adjusting for multiple comparisons or the confounding of media coverage, leading to concerns about the increased risk of obtaining false-positive results. In this study, we aimed to apply statistically more favorable methods to validate the earlier GT-based COVID-19 study results.

methodsWe extracted the relative GT search volume for keywords associated with COVID-19 symptoms, and evaluated their Granger-causality to weekly COVID-19 positivity in eight English-speaking countries and Japan. In addition, the impact of media coverage on keywords with significant Granger-causality was further evaluated using Japanese regional data.

resultsOur Granger causality-based approach largely decreased (by up to approximately one-third) the number of keywords identified as having a significant temporal relationship with the COVID-19 trend when compared to those identified by Pearson or Spearman's rank correlation-based approach. "Sense of smell" and "loss of smell" were the most reliable GT keywords across all the evaluated countries; however, when adjusted with their media coverage, these keyword trends did not Granger-cause the COVID-19 positivity trends (in Japan).

conclusionsOur results suggest that some of the search keywords reported as candidate predictive measures in earlier GT-based COVID-19 studies may potentially be unreliable; therefore, caution is necessary when interpreting published GT-based study results.

Indexed as

COVID-19Search EngineCommunicationHumansJapanSARS-CoV-2COVID-19Google TrendsGranger causalityInfodemiologyVector autoregression model

Identifiers

PMID34275447
PMCPMC8286439

What Socratic holds

Textmetadata
LicenceCC BY
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Registered trials

None linked

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 Socratic graph.