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Questions tagged [survival]

Survival analysis models time to event data, typically time to death or failure time. Censored data are a common problem for survival analyses.

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What is the bandwidth in a hazard rate plot?

I am doing some Survival Analysis using SAS. On the Hazard Plots I noticed some values on each curve labeled "bw" which after some research, I assume it means bandwidth. However, after much searching, ...
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1answer
10 views

Differences between Wald Statistics and P-values obtained with Dummy Coding vs. Direct Coding in Cox Models

Using the larynx dataset (source: Survival Analysis Techniques for Censored and Truncated Data) to illustrate, supposing you want to estimates the hazard rates of event for stages 2 and stages 3 ...
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15 views

Underlying Poisson Distribution in Cox Regression with censoring

My question stems from this post: Does Cox Regression have an underlying Poisson distribution? Cox regression with no censoring can be interpreted as Poisson regression. Can we interpret Cox ...
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8 views

Survival-analysis dataset problem [on hold]

I need to analyze the duration of an event over the years depending on time variant variables, how can i setup my dataset? I already tried to do a panel data in which i record the variables for every ...
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12 views

Comparing survival rates

The question I have is focused on comparing remission rates at a fixed point in time. For example, I have cancer type A and cancer type B (the two are not mutually exclusive groups) and all patients ...
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0answers
17 views

How can I change the 'baseline hazard function' from its default?

I have implemented a gap time-conditional (aka PWP) recurrent Cox regression model in R. However, rather then baseline hazard function (delta_0(t)) acting as a constant, I would like to incorporate a ...
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13 views

Relationship between survival probabilities and cox proportional hazard parameter estimates

I am building a home lending model through Survival technique. Since, I wanted to use a lot of time varying covariates (change in marital status, cash balance, residence etc.), I decided not to go ...
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11 views

Help with cox regression (survival analysis) [on hold]

I had a few questions about analyzing my data via cox regression. Relatively simple data: the effects of rainfall amount and frequency on survival of tadpoles in small ponds. Not too sure if this is ...
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26 views

Simulating survival meta-analysis data (with a random effect) [closed]

I would like to simulate survival meta-analysis in clinical trials on R but I'm not pretty sure of what would be the best way to do it and what would be fitting more the reality. The data would ...
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6 views

What's a simple explanation for risk and its formula in survival analysis, weibull regression

I have that if the model is $\ln(\mu_i) = \beta_0 + \beta_1 x_1$ where $x_1 \in \{0,1\}$ and represents tired (or anything suitable, sex, etc). The model also has a shape parameter, $\gamma$. ...
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7 views

Cox Model with time-varying covariates in mlr

I am using the mlr package in R to perform survival analysis. mlr includes the Cox Proportional Hazards Model (function coxph from library survival) as one of its integrated learners. As I understand ...
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16 views

Survival analysis of identical items in lifelines

I am doing survival analysis of hardware (more precisely, hard disk drives) and wanna predict HDD expected lifetime from its specs. I have a dataset of drives, where for each drive its lifetime in the ...
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7 views

How to model change in independent variable for Cox Proportional Hazards Model?

I'm interested in calculating a time to event model (Cox Proportional Hazards Model) and one of my independent variables has multiple measurements. I'm planning on using a time varying covariate for ...
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14 views

Survical model: get time-dependent survival estimates with nested random effect and repeated measurements

In an ecological experiment I have recorded survival of individuals in response to two different food items (treatment). Individuals belong to different families (random term) and are measured at 5 ...
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17 views

Cox regression with two events

We have a status variable with three events: 0) Censored 1) Relapse 2) Death We want to examine if two different types of medicine have a different risk on either death or relapse. How can we compare ...
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1answer
28 views

How to model survival panel data in R? [closed]

How do you model panel data in a survival model? I am unsure how to model repeated cases (or id) in coxph, since the common ...
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1answer
39 views

Using survival analysis in hockey analytics- Period 1 vs Period 2 as Treatment variable

In my article on hockey analytics, I answer how different are the rates of goals, shots, or hits from the NHL regular season to the playoffs (Playoffs are games played by the top 16 teams in the ...
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10 views

Interactions in Survival Analysis using lognormal models -how to interpret?

Do you know how to interpret the odds in Survival Analysis using lognormal models? UCLA stata page has an excellent example on how to interpret interactions in proportional models, but how to do that ...
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12 views

Log-rank test returning error code [on hold]

When trying to perform a log-rank test using the Survival package in R I run into the following error: ...
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0answers
29 views

Finding the limit of a quotient of hazard functions

Let $\lambda_i(t),S_i(t)$ be the hazard and survival functions of two populations for $i=1,2$ and satisfy that: $\frac{S_2(t)}{1-S_2(t)}=\phi\frac{S_1(t)}{1-S_1(t)}$ (1) I want to proof that $\lim_{t\...
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17 views

Why is Stata smothed hazard estimate pruned to interval?

I have played through this R example to calculate hazard estimates. I chased the whole thing through Stata and obtained a different graph, though. R graph: Stata graph: What's the rationale ...
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1answer
39 views

Time dependent variable in survival analysis using Cox regression

Trying to determine how to analyse a time dependent variable (rainfall) in a survival analysis. Two rows of example data for animal A and animal B as below: Each value next to the animal represents ...
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1answer
29 views

Mean Survival Time Under Weibull Model Using `survreg`

Under the Weibull parametric model, we assume the survival time $T \sim \text{Weibull}(\alpha, \lambda)$, with density $f_T(t) = \alpha \lambda (\lambda t)^{\alpha - 1} \exp(-(\lambda t)^\alpha)$. ...
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7 views

Standard Error of Mean Survival Time in Parametric Model

How do I estimate the standard error of the mean survival time under a parametric model? For instance, under the exponential model, we assume that the survival time $T \sim \text{Exp}(\lambda)$, with ...
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31 views

Multivariate Survival Type Regression

Survival analysis: I’m interested in understanding how to approach model construction for one that determines the probability of termination at a time t as well as an associated variable at a time, t....
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1answer
16 views

Survival analysis: why MEDIAN of third event outcome is NA always?

I am doing a survival analysis integrating gene expression based on normalized counts: a gene can be expressed at 'low', 'high', 'med' levels. Here is what I do: ...
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6 views

Order of factor in test.for.trend survminer/survMisc R packages

I have some problems with the results of the function comp() from survMisc and surv_pvalue() from survminer R packages. They ...
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17 views

Time dependent variable (daily rainfall) in a cox survival analysis

I'm trying to analyse the effect of rainfall (a time dependent variable) on animal survival. In order for an animal to be measured as 'survived' in my study it needs to be found for a minimal period ...
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1answer
36 views

Survival analysis with recurrent events with subjects that move in and out of risk periods

I would like to model a recurrent event with subjects that move in and out of risk over the course of the observation period of the study. I have data on the out-of-risk periods (start and end dates) ...
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1answer
27 views

How could I do parameter tuning with feature selection in R package mlr?

In this project, I am trying to tune the parameters(especially the step number parameter) of the CoxBoost model for survival analysis. I have more features than samples and many features are highly ...
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29 views

Risk classification with non uniform risk exposure (truncated observation period)?

I have N individuals who are exposed to a risk. The risk exposure is in year fractions (from 1/365 to 1). More or less 1/4 of the observations are exposed to the risk for an entire year. I want to ...
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0answers
9 views

How does survfit (survival package) deal with NAs in time?

I am a beginner in survival analysis so please excuse if this question is obvious. Following the tutorial https://www.datacamp.com/community/tutorials/survival-analysis-R#third I want to calculate ...
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60 views

Lasso-Regression on a casecohort with interval survival data (Cox-Barlow-Method)

My problem in a nutshell: I would like to do a lasso- regression in R on interval survival data with weights and there seems no package available which can handle lasso, interval survival data and ...
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0answers
20 views

Different starting survival/hazard in Kaplan-Meier/Cox-regression

I couldn't find an existing answer to this yet. If there is, please share the link. I wondered if there is a problem with Kaplan-Meier analyses or cox-regressions when already at the beginning of ...
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0answers
22 views

Calculation of propensity score using cox regression analysis

I want to assess the association of a treatment with survival time in patients. The background information of patients like age and severity differ between the treatment group and non-treatment group. ...
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1answer
50 views

How to interpret CoxPH survival regression

I have a time to event data. Where 20% of the events are observed, so, 80% of the events are censored. Using this data I developed a CoxPH model using python ...
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1answer
20 views

Survival Analysis Time Dependent Variables

I am currently learning Survival Analysis for a project and I struggle a bit with the notion of Time-Dependent Covariates. Let's take the following example: I would like to know what is the ...
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1answer
59 views

Simulation censored data in R

I am trying to simulate a data set of interval censored data(finite interval censored data, right censored data ,and left censored data). In fact, I created two monitoring times in R and I have the ...
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0answers
23 views

predict continuous variable over time for each row

I have many items with a start date, which produce continuous outputs over time for a few months after the start date. These outputs often follow a decay function but not always. So it is a bit like a ...
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1answer
31 views

How can I check model assumptions in AFT survival model?

I am working with interval censored data and I am fitting an AFT model with the survreg() function from the survival package. ...
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0answers
9 views

How to deal with the problem of censoring in tree-based machine learning?

Censoring occurs when the outcome of a unit is not observed, because the unit is lost to follow up in a longitudinal study. Let $Y_t$ be the survival time at $t$. Then a unit is censored at $t'$ if $...
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1answer
19 views

In a time to event analysis, when is it appropriate to use parametric models to compute restricted means?

Restricted mean is gaining popularity as a substitute for the hazard ratios to compare survival times in time-to-event analysis, especially in observational studies where chances of violation of ...
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2answers
57 views

Linear predictor from coefficients of Cox PH model

I need to calculate the linear predictor of a Cox PH model by hand. I can get continuous and binary variables to match the output of predict.coxph (specifying 'lp') but I can't seem to figure out how ...
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1answer
22 views

How to estimate the hazard function?

I model the survival data with a piece wise constant exponential distribution at time t. Let R be the total number of the population at time t, and D be the number of deaths observed at time t+dt. So, ...
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0answers
21 views

Discrete-time survival model as linear probability model

I am trying to fit a discrete-time survival model. This is easily done by fitting a logit (or probit or complementary log-log) model of failure on time and on the covariates of interest. Standard ...
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1answer
32 views

Survival Analysis - Relationship between CDF and survival function

I am trying to teach myself survival analysis and I followed this youtube video. The video states that given: $ F_x(t) = \Pr[T_x \leq t ]$ is the future probability of the life for a person who has ...
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0answers
13 views

Statistical test on Proportional Hazards Assumption

Usually the scaled Schoenfield residuals and related test (e.g. cox.zph) are used to show that the proportional hazards assumption is not violated. I would like to show that the proportional hazards ...
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0answers
9 views

In what case KM estimator and NA estimator gives the same result?

I have a survival dataset which includes three explanatory variables(gender, race and ethnicity), a "time" variable which records event time or censoring time and an "event" variable recording whether ...
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0answers
26 views

A survival (accelerated failure time) regression model for censored data across several trials

I have this experimental design: Two groups A and B. Individuals from group B were genetically manipulated such that when they are given a certain drug the drug turns on a gene that was inserted ...
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1answer
44 views

How to interpret hazard ratios of Cox output?

I'm really struggling to understand how to interpret my R outputs in terms of hazards ratios. I have ran a Cox proportional hazard regression to compare survival between 2 treatment groups (neutron ...