Survival analysis is concerned with modelling the time before subjects change state, typically time until death or failure. One key feature of such data is that they can be censored, that is, some subjects will not have changed state before the study ends.

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Model Selection with Competing risks in Cox regression

When doing cox proportional hazards regression one often has competing risks. The typical approach for this is to fit separate cox proportional hazards models for each risk, censoring the competing ...
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29 views

R adds unexpected variable to interaction model

Not sure if this is more of a programming question (in which case please move to stack overflow) or a statistical model question (in which case, please read on!) I'm exploring a data set and doing ...
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1answer
20 views

Study Length Over-Estimating Hazard Ratio?

Are cox model studies over too long a time-scale at risk of over estimating (or under estimating) a covariate's effect on hazard? I'm studying inbreeding in a captive animal population. Some ...
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24 views

Survival analysis with competing risks

I am analysing the effect of an intervention to reduce length of hospital stay (LOHS) after surgery. The main outcome is LOHS and the intervention is the main exposure. Death while in hospital is an ...
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1answer
45 views

Comparison of predictive models

I am trying to compare the predictive ability of various models in predicting survival in patients. I would like to examine the predictive performance of each model using 4 tests: squared Pearson ...
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22 views

What does muhaz return?

A pretty basic question. I have read somewhere that the muhaz function in muhaz package will return the baseline hazard rate for COX model. The muhaz document states that it "Estimates the hazard ...
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Survival analysis for matched set cohort data - Methods for absolute and relative risks?

BACKGROUND I have a matched data set with 10,000 cases and 20,000 controls. Cases are defined as such due to a diagnosis of COPD (Chronic Obstructive Pulmonary Disease - a lung disease caused by ...
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23 views

Survival Analysis on Telecom Churn in R

I am working on Telecom Churn problem and here is my dataset. http://www.sgi.com/tech/mlc/db/churn.data Names - http://www.sgi.com/tech/mlc/db/churn.names I'm new to survival analysis.Given the ...
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1answer
36 views

Estimating mortality using Cox model with baseline

I have been reading online notes and papers on how to build survival models using CPH, and I think I've a good idea how things work. However, there are two questions I still have in mind: 1) let's ...
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error message while doing surv_test [migrated]

I am trying to fit surv_test to a Surv object Surv(time, event==1) inorder to do an exact ...
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Rate table in package survexp.fr in R [closed]

I would like to calculate the similar parameters produced by SMR(...) in SURVEXP.FR package. The question that I have is if I ...
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Dealing with non events in one treatment group - survival analysis

I am currently trying to apply survival analysis to several tree species which were monitored for growth and phenology for 4 years and seperated into three treatment groups. From this data I have ...
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1answer
26 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 ...
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What is the survival function for a Weibull model with one covariate?

What is the survival function for a Weibull model with one covariate? I can find the survival function for a model with an intercept only, but I'm having trouble finding how to find the survival ...
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Multivariate survival with recurrent events and spikes back to 100% alive

I am trying to solve for what seems to be a multivariate survival model, but am getting stuck as there are both recurrent events and also jumps back to 100% alive. Rephrasing the larger project in ...
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1answer
50 views

Prediction with categorical variables in Cox regression

I'm doing survival analysis with Cox PH. I have my final model based on averaged models and I have four categorical variables with multiple levels each. I computed the fitted values using ...
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10 views

Evaluating survival models in the presence of covariate-dependent censoring

I have a censored survival analysis problem with the following characteristics: Failure times are discretized The censorship distribution depends on certain covariates I don't have a ...
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1answer
37 views

Using random forest for survival analysis with time varying covariates

I've been trying to train a model that predicts an individual's survival time. My training set is an unbalanced panel; it has multiple observations per individual and thus time varying covariates. ...
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62 views

Cox Models treatments depending on time until event

I'm trying to get the "productivity" of treatments like sending an email, calling or sending an SMS and their combinations in the paying debtor's probability. I couldn't find one model that satisfies ...
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79 views

Violation of Cox Proportional Hazards by a continuous variable

[This question is related to 1 and 2 on this site.] I fit a Cox model with these three time dependent variables: {s:numeric, C:binary, l:numeric }. I have 1069 ...
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Censored data from a truncated distribution (Stan)

I'm trying to write a survival model of fossil species durations. In this case, the minimal possible duration for a species is 1. Also, the general idea in paleontology is that we are only observing a ...
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23 views

Akaike information criterion for Cox proportional hazard models

I am conducting an analysis of survival data using Cox proportional hazard (CPH) models, to figure out what is the best model to use. The models I am comparing are non-nested. My plan is to compute ...
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26 views

Question about piecewise exponential distribution

This is an excerpt from the following paper. I am particularly interested in knowing how the authors got the displayed equations. We let [Z] denote the distribution of a generic random variable ...
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4answers
132 views

Determine where hazards starts to increase for a continuous variable

I'm interested in a continuous variable, namely blood pressure. The higher the blood pressure, the greater the risk of heart attack and stroke. However, studies frequently report that also low blood ...
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1answer
51 views

What is a hazard rate?

What is the definition of a hazard rate? What is a hazard function? I thought it was the probability that a unit does not survive the time period conditional on being alive, but I see hazard rates ...
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50 views

Survival models and differential equations

I have a question regarding survival models and differential equations. Is it possible to translate survival models ( in survival analysis) into differential equations? For example can we write the ...
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20 views

Approximating cox model with time varying covariates using poisson

How do you reformat a dataset in order to perform a cox regression with time-varying covariates as a poisson regression. I'm trying to run a survival analysis regression in python with time varying ...
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Cross-validating a survival model with right censoring?

Is it sensible and possible to cross-validate a survival model? Does it depend on whether there is censoring? If not, why? If the answer depends on the model, then answer for common survival models ...
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Is calculating r2 appropriate for cox mixed effect models?

I'm looking at the effects of inbreeding on survival in a captive animal species. I'm trying to clearly distinguish the effects of inbreeding from other possible random genetic factors on survival. ...
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29 views

Getting the 1 and 3 years overall and progression-free survival (OS&PFS) and their p values in SPSS

I have a cohort of 300 subject divided into two groups (e.g. chemo y/n). The Median follow-up is 18 months (range 1-87). There were 45 deaths so median survival was not reached. I have compared ...
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39 views

Fitting Cox Regression / Proportional Hazard Model with x time interaction term in R

I am asking this in the context of wanting to diagnose for violation of proportional hazard assumption and its correction. (Schemper 1992) On p.179 of Hosmer, Lemeshow and May, it says that we can ...
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1answer
31 views

Specifying the LHS for a proportional-hazards survival regression

This is a basic question to understand how datasets for survival analysis are constructed. I understand the terms in the model, given by this equation: (P.41, G. Brostrom, "Event History Analysis ...
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1answer
18 views

Time dependent covariate SPSS

I am attempting a time dependent covariate analysis using SPSS but end up running into some difficulties. This is the first time I am trying it using SPSS so would appreciate some advise or direction. ...
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1answer
57 views

Ignore strata in external validation of stratified Cox prop hazards model?

I've fit a stratified Cox proportional hazards model to some survival data, where I've stratified by a potential confounder which is the batch the data comes from (there are three batches). Now, I'd ...
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1answer
54 views

Survival analysis where P(event) < 1

Suppose you are interested in analyzing time to event data for a sample of patients. You are interested in the time elapsed until a patient contracts an illness. However, a majority of patients will ...
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1answer
37 views

Calculating probabilities using cox regression [duplicate]

I have done a multivariate Cox regression in R. The model fits to my data very well. Now, I would like to use my model and predict the survival probabilities of new observations. I am unclear how to ...
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Plotting the effect of a variable estimated by a regression model fit

Plotting the effect of a variable estimated by a regression model fit is quite interesting. However, I have some questions regarding this subject. Here is some example code: ...
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1answer
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The Definition of “Approach infinity at rate n”?

In p.62 of the textbook, "Statistical Models and Methods for Lifetime Data" second edition, (Jerald F. Lawless, Wiley, 2003) it states "An added requirement is that the sequence of fixed ...
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Perform logrank test only with survival probabilities

So I have survival probabilities for 2 groups at years 1, 3, 5, 10,15. Is there way to detect significant differnece between all of them as a whole or even between each pair? I don't have the ...
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2answers
51 views

Estimating expected lifetime from hazard ratio and estimated base hazard function

Apologies if this is a basic question, I am not very familiar with survival analysis ... I have trained a gradient boosted Cox proportional hazards model in R, and have been able to obtain reasonable ...
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1answer
54 views

Weighted Kaplan-Meier Curve Log Rank Test

I need to compare two weighted KM curves created by using the svykm function from the survey package. I am unable to find any ...
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1answer
53 views

AFT model with time varying independent variables

I am a newbie in survival analysis and I would like to pose some simple questions, after reading numerous posts regarding how to perform survival analysis in R. So, what I would like to know is: Can ...
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1answer
124 views

model selection through shrinkage (Lasso) using glmnet

I would like to use model selection through shrinkage (Lasso) using glmnet. After trying the example of the glmnet manual and tried the procedure with my data. ...
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1answer
104 views

Impute missing values using aregImpute

I have a data frame with 61 columns. Some data is missing. I read in Steyerberg's book about aregImpute in Hmisc. I used it with ...
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Expected survival time: comparisons when measurements are an average over other measurements?

Set up We have a few types of interventions. For each intervention, a failure occurs randomly at some time $t$ after start for each subject. We take $n$ measurements of $t$ using $n$ subjects, and ...
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31 views

Joint Models vs the 'usual' time-dependent Cox regression for time-varying predictors

I've got a methodological question, and no data set attached. Suppose I aim to fit a proportional hazards model (Cox) for survival data. I have multiple observations for each individual (data in long ...
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1answer
50 views

Time-dependent covariate in extended Cox model

In Cox's PHM, $$ \lambda(t;\mathbb{x}) = \lambda_0(t) \exp(\beta^T \mathbb{x})~, $$ it is well known that the effect of a time - independent covariate on the survivor function is to raise it to a ...
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1answer
103 views

How to evaluate the goodness of fit for survial functions

I am a newcomer to survival analysis, although I have some knowledge in classification and regression. For regression, we have MSE and R square statistics. But how we can say that survival model A ...
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1answer
66 views

Simulate time to event times based on an existing subset of data

I have to task to predict data volume to be processed for a study that currently has 40 patients, but will have 100 patients eventually. Since most of the data is generated during the treatment phase, ...
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Best way to examine mortality tables?

I have a set of tables containing mortality rates (hazard rates) and I want to see how well these values reflect the influence of the covariates (age, sex, issue year, etc.). I also have actual ...