# Questions tagged [logrank-test]

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### In log-rank testing how could the CI cross 1 with a p-value < .05?

Came across these results comparing standard therapy with standard therapy and atezolizumab in endometrial cancer. Findings state survival in placebo group vs treatment as HR 0·82, 95% CI 0·63–1·07; ...
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### Log rank test for a time-dependent variable?

I am studying the association between a time-dependent treatment variable and death. The treatment is time-dependent because patients can switch groups during the follow-up. I followed [this paper] (...
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### What statistical test to compare survival curves for dependent data?

I'm currently doing time to event analysis for a cohort of participants. Each participant completed two different diagnostic tests for the same virus, and they did these every day for a week. ...
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### Earliest paper on stratified log rank test

What is the earliest paper that proposed the stratified version of the log-rank test? Unfortunately, finding citations/references in textbooks for established statistics procedures is difficult.
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### Survival analysis with missing values for some variables

I'm performing a survival analysis. I did the univariant Cox regression model for all my variables (about 40). I even performed the univariant analysis in all those variables that had missing values ...
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### Minimum follow up period survival analysis

Imagin there's a surgery for a disease A that can cause a disease B. The minimum period to diagnose the disease B after the surgery of the disease A are 3 monthts (before that period of time, we can't ...
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### Univariant analysis in survival study

I don't know a lot about statistics and survival analysis so this might be a dull question. I'm performing a survival analysis where I want to study the possible risk or protective factors that could ...
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### What kind of logrank test is performed by survdiff function in R?

Information added: this question is not duplicate, neither my question nor the question in the link had been solved at all, I added more info to see if you can see the problem I was trying to ...
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### Using maximally selected log rank to find two cutoffs instead of one

I have used the maximally selected log rank test to dichotomize a continuous variable (high vs low). I was curious if the maximally selected log rank test could be generalized to make 3 groups instead ...
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### Left Truncated Data survival data

I am working with a data that is I believe left truncated. I am looking at how Veterans with MPNs have a different timing of arterial thrombosis (AT) compared with Civilians with MPNs. In the data ...
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### Log-Rank test with propensity score matched data

Let's assume that I have two groups that I would like to compare in terms of death rates. One group (group A) got a specific treatment and the other group (group B) did not get any treatment. I ...
1 vote
507 views

### Log-rank and cox regression showing contrary results

I got contrary results from my log-rank (not significant) versus my cox regression (significant) regarding the effect of my treatment variable with the aim of hypothesis testing. That's no real wonder,...
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### How to compare groups when one treatment group has no events and the treatment variable is time varying - survival analysis

I am comparing two treatment groups and I have 3 different types of outcomes. The dependent variable, treatment, is time dependent and so I conducted time dependent cox regression for each of the ...
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### Interpretation of Log-rank test with "close" survival curves

I have a question about the interpretation of the log-rank test, when the survival curves (in the figures below hazard curves) are close together. Below you can find two figures with survival curves ...
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### Is it appropriate to use log-rank test in a study having multiple cases with expected values less than 5?

My goal is to show independency of factors related to survival of a small size sample (26 patients) for a period of time, this sample was divided in 2 groups (16 vs 10 patients), the events were ...
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### Appropriateness of log-rank test [duplicate]

I'm working on factors related to survival of a small size sample (26 patients) for a period of time, this sample was divided in 2 groups (16 vs 10 patients), the events were little (7 in total). I ...
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### Can the Log-Rank Test be used for feature selection?

Chi-squared can be used to test independence and if independence is present, the variable can be dropped. Does the log-rank test work the same way since it is tied closely to the chi-squared test?
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### The link between log-rank test and KM estimates

I have taken the survival analysis class a few years ago, and we have learned both Kaplan-Meier estiamtes for survival curves, and the log-rank test for inferencing the difference of hazard rate ...
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### Is log-rank parametric or non-parametric test, and why?

How is the log-rank test a "non-parametric test" according to wikipedia.org if one has to specify the parametric survival model for this test? We may run log-rank under the assumption of ...
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### Does log-rank statistic converge in distribution to a beta distribution or Pearson I distribution?

The logrank test statistic compares estimates of the hazard functions of the two groups at each observed event time. It is constructed by computing the observed and expected number of events in one of ...
1 vote
966 views

### How to conduct Cox-regression with time-dependent covariate and estimate K-M plots (including log-rank test)?

I want to conduct a Cox-regression with time-dependent covariate and other control variables and estimate K-M plot with log-rank test result. I will take the heart transplant as an example, some ...
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### When having non-proportional hazards, should I use stratified Cox by time or Logrank tests within periods?

My data have non-proportional hazards with clear separation. Should I handle it via stratified Cox regression or using separate Log-rank test within subsets? I will use R only to illustrate. I want to ...
42 views

### Can I use Cox model to compare two survival function similarity like log-rank test? [duplicate]

My question is as the title emplies, can I use cox model to measure the difference (or similarity) of two survival functions, just as log-rank test does? And if so, how? Thanks in advance!
1 vote
117 views

### Median Survival Time for Clinical Trials

I have a Clinical Trial where I'll be comparing a drug vs placebo. Then I intend to run a Log-rank test on it. Now for the sample size calculations, I would be requiring the hazard ratio and the ...
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### Sample size calculation for a three arm clinical trial study

I have a 3 arm clinical study with two drugs and placebo on the three arms respectively. I intend to perform a Log-rank test on it. I would like to know about the best software which is globally ...
1 vote
629 views

### Will stratified log-rank test work if there is no event in some small strata?

Since the analysis is for a rare event, it is possible that some small strata have no event. Hard to predict. Just wondering if there will be any problem. Cox PH model will have problem for sure, but ...
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### Type II error for survival analysis

I am a beginner and I have been looking all over the internet and books to find an answer to the folowing question (but haven't been able to find the answer): I have observatoinal data and would like ...
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### How to calculate the sample size for three groups (or >2 groups) by log-rank test in R?

We plan to conduct a study for comparing the survival rate between three different types of surgery for total knee arthroplasty. Thus, the sample size for the study should be estimated. Notably, how ...
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### Log-rank test: should I run it once for the whole follow-up or also test for shorter time periods?

Let's assume we have a 5-year follow-up for survival for two groups, and I report their crude mortality rates for years 1, 2, 3, 4 and 5. After that, would it be reasonable to test the mortality ...
195 views

### How to get adjusted logrank in the Cox model, if I have two covatiates?

Let's say I have a model (pseudolanguage): survival = My_Factor + sex + age. I do it to adjust the hazard ratio for sex and categorized age={<30yr; >=30yrs} (not my choice). I can get two p-...
815 views

### R: Survfit function - getting p value when specifying start.time

I would like to make a Kaplan-Meier curve for data on an alternate timescale. I'm interested only on events happening after 6months followup, so I use the ...
715 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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