Questions tagged [logrank-test]

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16 views

Why use a stratified log-rank test if we balance over strata anyway?

When comparing survival data over time, we can use the log-rank test. An extension of this is the stratified log-rank test, which adjusts for variables. Let's say we wanted to adjust for the effect of ...
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1answer
36 views

How do I get 1-, 3-, and 5-year survival with survival analysis in SPSS?

I have a database with patients and did survival analysis in SPSS. SPSS gave me the mean and median survivals with 95% confidence intervals. However, I also want the 1-,3-, and 5-year survival times ...
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1answer
27 views

Test for difference in hazard in two consecutive time periods

Let's say I have data on times-to-failure for a group of mechanical components in two consecutive years, Year 1 and Year 2. I would like to test the hypothesis that the hazard rate/survival behaviour ...
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1answer
21 views

Survival comparison among two different groups

I have two groups of patients, let’s say groups A and B, who have the same disease with a well-known genetic cause. My main goal is to see whether there is a difference in survivals by the type of ...
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2answers
46 views

Is logrank test and its variations affected by the inequality of classes?

I am currently dealing with an home made exercise which compares the lifetime of patients who made use of a specific drug or not. For simplicity, I decided to remove censored data, but as replacement ...
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0answers
16 views

How to use log-rank test for panel data?

Is it possible, and if yes how, to compute log-rank test to compare effects in (unbalanced) panel data, i.e. longitudinal study ? What are the possible problems which might arise ?
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1answer
49 views

Survival Analysis when Independent Variable Proportions Shift Heavily Over Time

I am attempting to conduct survival analysis on hiring processes with Kaplan-Meier, where the event is termination from the organization: testing a few independent variables known at an employee’s ...
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0answers
33 views

What is a dragon king?

I am studying a system of cities where the largest city appears to be in many aspects an outlier. The distribution of city size - in any country - are often claimed to follow Zipf's law. According to ...
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1answer
30 views

Compare p-values of equal sample sizes: What does it mean if a p-value of kaplan-meier log rank test is larger than the other?

I'm analysing detection rates of carcasses for birds and mammals in either open fields or in forests, using kaplan-meier survival functions. The p-value is determined by log rank test. I found that ...
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1answer
24 views

Which test should be used to compare crude mortality between 15 groups?

I have fifteen groups (factor levels) and I need to compare their crude mortality. Is Logrank test limited to two groups only? Which test would be correct to use in this case?
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1answer
259 views

The logrank test statistic is equivalent to the score of a Cox regression. Is there an advantage of using a logrank test over a Cox regression?

I have understood the logrank test as a "safe" or "conservative" way to check for a difference between two survival curves. It is "safe" in the sense that it is a ...
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0answers
15 views

Question on svylogrank() in survival package

I am running a survival model with sampling weights and was hoping to get the weighted logrank test results. When I use the svylogrank() function from the survey ...
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0answers
140 views

Difference between p-value in log rank test and cox proportional hazard?

For survival analysis I've used log rank test and the cox proportional hazard model, but I got different p-values with the same columns in this models. I looked into the cox proportional model, but ...
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1answer
158 views

Difference in log-rank, tarone-ware, gehan-breslow, Peto-Peto etc

Everything is already in the title. I study survival analisys Could you tell me what is the difference among log-rank, tarone-ware, gehan-breslow, Peto-Peto etc.....
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1answer
135 views

Is it possible to compare survival curves from different models (Cox and Fine-Gray)? Ideally in R

I would like to perform a time to event analysis on some biological example with animals. The event of interest is a terminal event X. But the animal may die from other reason before it happens. So I ...
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1answer
852 views

Why is likelihood ratio test preferred Cox model for small sample sizes?

It looks like a common consensus that likelihood ratio (LR) test is preferred over log rank and Wald in Cox model when sample size is small. I did some research and couldn't find any clear answer My ...
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0answers
269 views

Why are Logrank, Wald and likelihood ratio test asymptotically equivalent?

I am trying survival analysis and it seems like a common consensus that Logrank, Wald and likelihood ratio are asymptotically equivalent I don't understand why they are asymptotically equivalent. As ...
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1answer
307 views

How to calculate log-rank test statistic

Depending on which statistics text you read you will get 2 different formulations of the log-rank test statistic. In some texts you will see it specified as: $$ \frac{(O-E)^2}{E} $$ Example 1 Whilst ...
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2answers
158 views

How to properly do a Survival analysis - Question about start times

I have a monthly report that lists transactional errors made by facilities all over the country. Each row is a single error and the columns represent descriptive information about each error (ID, ...
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0answers
59 views

How can we analyze a dataset with a pseudoreplication problem?

I am trying to analyse a data set with a pseudoreplication problem and would be grateful if someone could give me some guidelines on the best way to deal with it. We have a set of subjects exposed to ...
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1answer
99 views

How should I decide which test to use to look for differences in Kaplan-Meier curves?

I'm conducting a survival analysis for my dissertation and have run into a bit of a road block about which test to use to look for differences in Kaplan-Meier curves between treatments. A previous ...
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1answer
1k views

R calculate log-rank p-value of survival curve at specific time [closed]

I am using survfit object from package survminer to draw a survival curve in ggplot. Now I am trying to understand how I can use ...
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1answer
4k views

Logrank p-value for >2 groups

I'm reviewing a paper that includes some survival plots for patients stratified to 3 groups (low, intermediate and high value of certain parameter), with p-value given for each plot. My understanding ...
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0answers
46 views

Cox Regression Model for toxicity

I'm trying to evaluate the toxicity of a certain treatment over time. I have 2 independent groups and I apply a treatment to one, and nothing to the second one. I thought about using logistic ...
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0answers
245 views

Survival Analysis: Significance in LogRank but not in Cox Regression

Currently, I am trying to extract the HR and 95% CI from a kaplan meier curve (used DigitizeIt plus the spreadsheet provided by Tierney et al) [Tierney JF, Stewart LA, Ghersi D, Burdett S, Sydes MR....
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1answer
154 views

How to deal with different likelihood of censoring across groups in survival analysis?

I am analysing survival data for nematode worms fed on four different bacterial diets (four groups). Each group has at least 70 events (deaths), but there is often a very uneven proportion of ...
1
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1answer
266 views

sample size calculation for one-sample log rank test with interims (ie group sequential)

I wonder if there is any advice for performing a sample size calculation for survival data using the one-sample log rank test with interims (ie group sequential) - ie with O'Brien-Fleming or some ...
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0answers
72 views

Is Univariate comparison of 10 subjects using log rank test in Kaplan Meier survival is statistically sound?

I have 10 subjects and want to analyse the predictors of overall survival and progression free survival using log rank test . Will conducting log rank test on such a small sample size will be ...
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0answers
69 views

A strange finding with the logrank test statistics

When I try to confirm the type I error rate of the logrank test by simulation, I found something strange... Firstly, I generated 100 observations from exponential distribution with lamda1=1 as group 1 ...
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1answer
769 views

Can coxph be used for categorical data?

I'm doing some survival analysis and I got the idea to change a binary variable into three-category variable by sub-dividing one category of the binary variable into two new categories. Here's a ...
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1answer
317 views

Version of Mann-Whitney U test, for right-censored data

Is there an equivalent of the Mann-Whitney U test, but for right-censored data? I have right-censored numerical data from two different groups. The mean for one group is higher than the other. I'd ...
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2answers
786 views

how can I focus the log rank test in a selected period of time of follow up?

I am using R survdiff (survival package). I would like to focus the analysis on the first 2 years of my survival curve (that is actually much longer, but with few cases in the long term and with ...
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1answer
70 views

Uneven (right) censoring where the time of truncation is constant

I've collected data comparing the relative success of two different groups of participants on finding the answer to a difficult question. The problem is that not all the participants in the control ...
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0answers
87 views

Is there a reason chi square tests are used over normal tests in survival?

I've been reading and programming a bit about survival, and it seems that a lot of statistics are normally distributed (and thus, their square is chi square distributed). For example, the log rank ...
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0answers
804 views

Reproducing the cox model score test in R

I am using R and would like to recreate by hand the values of the tests. For example, ...
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2answers
2k views

Survival analysis: log rank or ANOVA to compare groups?

If I want to know whether there is a significant difference in age of onset between the 2 groups, should I use ANOVA? My data meet the requirements of an ANOVA test. Or should I use the log rank test, ...
0
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1answer
946 views

One-Sample Log-rank test statistic

Ok, I am totally confused, this is probably a pure math rather than a statistic question but please enlighten me. I found the logrank statistic formula being reported in the literature in 2 ways, but ...
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3answers
500 views

How can you have p < 0.0001 with a sample size of 89 and a control group of 52?

From Efficacy of monoterpene perillyl alcohol upon survival rate of patients with recurrent glioblastoma (linked from Does Frankincense cure cancer?): Patients and methods It was included 89 adults ...
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0answers
475 views

Survival probability for a case-control study

I have a case-control study in which 21 patients with a certain clinical outcome and 20 patients without that clinical outcome were (retrospectively) selected from a larger group of patients who were ...
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0answers
58 views

Very puzzling - naming the endpoint of survival analysis

A question that should be straightforward for statisticians but is puzzling me to the point I am nervous. I am doing a PhD in Epidemiology and am going to use Cox regression. The predictor is a ...
1
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1answer
629 views

Relative Risk with Log-rank test

I always associated/used log-rank test to evaluate Hazard Ratios. However, a well-known professor is using/presenting results of log-rank test for Relative Risk and Risk Ratio. Can anyone explain ...
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0answers
974 views

Matlab survival curve log rank test

I am trying to do survival analysis in matlab and want to calculate log rank test scores among several curves. I found a possible code to do log rank here. But based on its description, it can only do ...
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2answers
12k views

How to calculate the HR and 95%CI using the log-rank test in R?

The R survival package is very useful to do survival analysis. And I know the survdiff function can be used to compare the difference of survival time in two or more groups. And the p-value number can ...
5
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2answers
2k views

Log-rank / Cox analysis with very unequal sized groups: alternative calculations of p-value?

I would like to set up a series of tests on the difference in survival between two very unequal sized groups. Generally either log-rank (using the R survdiff function) or a cox regression (R coxph) ...
5
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2answers
26k views

log-rank test in R

I need to use the survdiff function to statistically compare (using log-rank test) the following survival functions: (1) Male (Sex=1) and Female (Sex=2) (2) ...
5
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2answers
3k views

Logrank test for trend (proportional hazards)

How one can create a logrank test for trend and does it differ from normal logrank test? Any suggestions or literature? Maybe some R examples and functions?
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1answer
638 views

Validity of Log-rank p-value when there are zero events in one group?

I am looking to do a Kaplan Meier analysis to look at survival in two groups. I have 21 people in group A and 17 people in group B. 5 people in group B died at various times, 0 people in group A died, ...
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1answer
4k views

Sample size / power calculation for logrank survival test

I have really little idea of survival analysis. I am aware that logrank is a special case of Cox' proportional hazards model, and that tons of R packages and scripts address the problem of power / ...
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0answers
98 views

Error in books formula concerning the log-rank test?

I am currently reading the following book: Clinical Trials: A Practical Guide to Design, Analysis, and Reporting by Duolao Wang, Ameet Bakhai (2006) On page 243-244 there is an example about the log-...
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1answer
2k views

In which situation does the log-rank test have low power?

This question is complementary to question 1 asked by @Jesse here. It is about the case when we don't find a significant result when performing the log-rank test and when the proportional hazard ...