Student or educator? Sign up with your school email and get 6 months of Pro free.
Cited by 824

The DOI matches its Crossref record; 1 of the 1 references it cites were found in a registry or an index.

Survival probabilities (the Kaplan-Meier method)

Open access
Bland, J Martin, Altman, Douglas G·1998·BMJ

Abstract

As we have observed,1 analysis of survival data requires special techniques because some observations are censored as the event of interest has not occurred for all patients. For example, when patients are recruited over two years one recruited at the end of the study may be alive at one year follow up, whereas one recruited at the start may have died after two years. The patient who died has a longer observed survival than the one who still survives and whose ultimate survival time is unknown. The table shows data from a study of conception in subfertile women.2 The event is conception, and women “survived” until they conceived. One woman conceived after 16 months (menstrual cycles), whereas several were followed for shorter time periods during which they did not conceive; their time to conceive was thus censored. View this table: Time (months) to conception or censoring in 38 sub-fertile women after laparoscopy and hydrotubation2 We wish to estimate the proportion surviving (not having conceived) by any given time, …

Overview

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1136/bmj.317.7172.1572

Cites

1 of 1 references verified0 citation errors · 0 not checkable

Statistics

Verification

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Citations

Cites

Show all 1 references

Cited by

See all 824

Metadata

Authors
Bland, J. M., & Altman, D. G.
Venue
BMJ
Publisher
BMJ
Published
1998-12-05
Volume
317
Issue
7172
Pages
1572-1580
ISSN
  • 0007-1447 (ISSN-L)
  • 0959-8138
  • 1468-5833
OpenAlex
W1503899947
Cited by
824
References
1
FWCI
4.82
Type
journal article
Language
en
Open access
bronze

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review

How to cite

Cite CoChat for the checks on this page, and the paper for its own findings.

This page
CoChat. (2026). Citation check: Survival probabilities (the Kaplan-Meier method). https://app.cochat.ai/papers/10.1136/bmj.317.7172.1572
The paper
Bland, J. M., & Altman, D. G. (1998). Survival probabilities (the Kaplan-Meier method). BMJ. https://doi.org/10.1136/bmj.317.7172.1572

Data sources

Bibliographic data: Semantic Scholar, OpenAlex, Crossref.

Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).

Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.