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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Applying Cox proportional hazards model to new data to get absolute risk (Framingham risk score)

I'm trying to apply one of the Framingham cardiovascular event risk scores to a new dataset in order to get absolute risk. D'Agostino 2013 "Cardiovascular Disease Risk Assessment: Insights from ...
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Addition of time before commencement of radiotherapy to Cox Model

I have a dataset from a clinical trial for which all cancer patients received radiotherapy, but at different times following surgical removal of their tumour. So more simply, I have a variable, time ...
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Can we find the Hazard Time by using Cox PH model for give covarites?

Can we find the Hazard Time by using Cox PH model for give covarites? I have built Cox PH model using the following equation. cph1=coxph(Y~tx+age+strat2) My output is ...
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41 views

Conditional expected lifetime in survival analysis

I want to do survival analysis with the Colon Cancer data in survival package: ...
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43 views

Survival Analysis why does probability drop to zero

I'm really new to stats and R and I suspect I'm missing something obvious. I have a set of memberships all who start after a point in time (six months ago). I have done my query to estimate the ...
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19 views

What's the best way to calculate survival time using outputs from random survival forest

I have built a random survival forest using R package randomForestSRC. The OOB error rate is around 10%. I was wondering whether anyone had some experience in utilizing the outputs from this model ...
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42 views

Survival analysis in R with left-truncated data

I am doing a survival analysis in R with the survival package. I think I am working with left-truncated data, but I'm not entirely sure how to handle it. I have a ...
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47 views

Predicting conditional expected lifetime by Cox model in R

I'm using a Cox proportional hazards model, estimate the hazard rate for Levamisole relative to 5-FU, adjusting for Age and Sex. ...
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estimate conditional time-to-event for recurring event history model

I have a sample of individuals for whom I have measured the time at which they display a particular behavior. This behavior is recurrent (it is not fatal). I have modeled these events with ...
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46 views

Survival Analysis—Equal follow up time

My question is whether my data are a survival analysis problem. I have 3 groups (2 interventions and 1 control). The 200 patients are all followed up for 6 months only. The follow-up is done by ...
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9 views

How to analyze survival data with possible temporal dependencies

I want to analyze some survival data. I have measurements of a biomarker (real-valued variable) before a first treatment, after that first treatment, and then after a second treatment (different to ...
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38 views

How to simulate survival times using true base line hazard function

I want to simulate survival times from the model $\lambda(t|X_1,X_2) = \lambda_0(t) \exp(\gamma_1X_1+\gamma_2X_2)$ where covariates are given by $X_1\sim$Binomial(1,0.5), $X_2\sim$Uniform(0,1), the ...
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Showing $ λ_V(x) \leq min\{λ_1(x),\cdots,λ_n(x)\}$ Hazard function

Suppose $X_1, \cdots, X_n$ are independent, nonnegative continuous functions, each $X_i$ has hazard function $\lambda_i(x)$. If $V=\max\{X_1, \cdots, X_n\}$, I need to show that ...
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Testing significance for pairwise Kaplan-Meier survival analysis between groups and pooled data

I've been working on putting together a survival analysis using Kaplan-Meier and the logrank test. I am doing the testing in R with survdiff(). Each plot has multiple groups/curves, and I've been ...
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28 views

Hazard model with time varying covariates

I am trying to build a discrete time event model. The event occurs once in 20 years period of time. Most of the example i saw use only covariates which are same over period of time. e.g. sex,race etc. ...
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Include interaction in multiple imputation - r

I'm doing some imputation models of time until recurrence of tuberculosis (Cox model). This model should include an interaction between the time and the outcome of the previous episode of disease (0- ...
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Error in adding interaction in Cox model?

I'm doing a survival analysis and after plotting the Schoenfeld residuals and test the significance of the correlation of residuals with time, I've decided to incorporate a interaction in the model. ...
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Correlation Matrix in an Event History Analysis - 11 years - 25 Variables

I'm currently writing my thesis, and I received feedback from my professor that i need to show the correlations between all variables during the time span of my research. N: 291 Years: 11 (2000 - ...
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Simulate censored data cox model

I would like to simulate interval-censored data in a Cox model. In the R package intcox I found the following code: ...
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Validation - correctly compare and validated imputation models

I've seen a lot of interesting questions here about multiple imputation and also great answers that helped me a lot to impute my data. I've used Predictive Mean Matching, EMB and I would like to use ...
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How to estimate the point of divergence between two continuous time survival curves?

In this experiment we collect $N$ samples and each sample yields a pair of survival curves. The two survival curves are hypothesized to be identical up until time $t$ and diverge thereafter. What ...
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How was this deviance formula for Cox Proportional Hazard derived?

The gbm package in R documents the following deviance formula for CoxPH models http://gradientboostedmodels.googlecode.com/git/gbm/inst/doc/gbm.pdf $-2 \sum w_i \delta_i (f(x_i) - \log(R_i / w_i)$, ...
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predicting manufacturing survival time

My task is to improve widget quality from a high volume manufacturing process. The survival data is 99% right censored, since most products do not fail, and rapid analysis long before failure is ...
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Cumulative Incidence Function - Competing Risks Discrete Time Survival Analysis

As I'm doing a competing risks survival analysis, I need to construct a cumulative incidence graph rather than a Kaplan-Meier survivor curve. However, in Stata, the command to construct this graph is ...
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What is the appropriate statistical test for Presence/Absence over time

I am assessing the presence or absence of a number of developmental milestones in mice in their first $21$ days of life. Each day, from the day they are born until they have $21$ days, I test if pups ...
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Censored data when censoring time is uneven

I have a data set relating to credit defaults. The data set contains around 100 predictors (some categorical and some numeric). I am interested in predicting the time to default, if the person ever ...
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Survival analyses for complicated models

I've just began looking into survival analyses, and I'm having some difficulty interpreting the results. I have a model linear regression model where time ~ x1 * x2 * x3... x9, this model seems to ...
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When is best to set the origin (time=0) point in a cox-propotional hazard model change analysis

I would like to know the relationship between change in a variable in the three months after a disease, and survival time. I have change in the variable in the first three months. But I am not sure ...
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22 views

Cox regression, survival, comparison with historic group, follow-up time

I have two groups of patients, treated at two time periods. I'm comparing survival. In the later group I have 3 years follow up time. In the early group I have of course access to longer follow up ...
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31 views

Cox regression with time varying covariates

I am looking for resources on Cox proportional hazards model with time varying covariates. I'm new to survival analysis so I'm looking for something not overly mathematical. I would also appreciate ...
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Finding overall survival in competing risk model

I am dealing with time until event data and there are three types of events that I am tracking Type A Death Type B Death Event C. Type B Death cannot happen unless C happened. At any given time ...
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Obtaining the outcome hazard ratio? [Survival analysis]

I am reading this paper: https://dipot.ulb.ac.be/dspace/bitstream/2013/96837/1/2011-025-ARIAS_DEHON-theroads.pdf On page 23 (of the paper, not the pdf) they have a table showing the "outcome hazard". ...
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146 views

Violation Proportionality Cox model - Repeat analysis?

I'm new to survival analysis, but I've been reading some papers and books and I got a nice model. However, one of the variables (Sit) does not met the proportionality assumption for the Cox model. ...
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How to calculate variance explained by an environmental variable in the model?

I have done some survival analysis, and used the following equation to calculate variance explained by environmental variables in the survival models: (DEV.-DEVenv)/(DEV.-DEVtime) where DEV. is the ...
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56 views

Error term interpretation in the Cox PH model

I am preparing a presentation on Survival Analysis models, with specific focus on the Cox model. I have been using such model (including its competing risks generalization) for some time now, but I ...
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unique spline for different groups in a linear model (and no spline at all for one group)

I have a problem that has puzzled me for a long time. It involves linear models and spline functions. I need to model "time since diagnosis" when some individuals never had a diagnosis. I use Poisson ...
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1answer
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Is there a limit to the number of time varying covariates in a discrete event history model

The case: I am investigating the impact of various predictors on the odds of migration using a discrete-time event history model within a multilevel framework. The outcome variable is dichotomous ...
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Method for determining correlation with “time since” or “time until”

I have samples of observational units that have a defined start and end date (not necessarily all equal in duration). I am trying to determine if an intermediate event is most closely associated with ...
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1answer
48 views

Hazard and density function in survival analysis with discrete time

I am running a survival analysis with descrete time. For that purpose I use the R package survival with this function ...
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What to do when complete cases vs. imputed cases and train vs. test disagree?

In a fairly complex survival analysis case with considerable missing data, I split the data set into training and testing and ran models for both complete cases and imputed cases (I used multiple ...
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Selection correction variable (non-randomly selected sample / bias) and Cox regression

I found an approach to calculate a selection correction variable for a Cox regression (Lee 1983. Generalized econometric models with selectivity. Econometrica 51: 507–512.): $$ λ = \phi \frac{ ...
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Interval censoring

I ran an interval censor survival curve with R, JMP and SAS. They both gave me identical graphs, but the tables differed a bit. This is the table JMP gave me. ...
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Testing proportional hazards assumption

Can you use the log rank test or the Wilcoxon test to test the proportional hazards assumption in the Cox model?
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1answer
62 views

How to predict when the next failure of a machine will be

I need to predict when the next failure of a machine will be. I have a long history of its past failures, repairs, and preventive maintenance. By common sense, I can guess there must be some ...
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1answer
110 views

p-value zero in hypothesis testing for survival curves

I have done survival analysis. I used Kaplan-Meir to do the survival analysis. Description of data: My data set is large and data table has close 120,000 records of survival information belong to 6 ...
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Survival analysis where covariates are unavailable for censored data

I am looking at the time required by judges to reach decisions. Each judge assesses a number of applicants and can either approve or not approve the application. The case is finalized when the judge ...
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How to have a captured response table for a 2-year prediction base Cox model in R?

My study is about "Churn Risk Evaluation of College Students". I decided to use R software, already had a result for the survival probability of an old data (all the students already left or ...
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How to check out an appropriate survival model?

Maybe this question is too general, but I think it's worthy to post to clarify me some standard procedures in survival analysis. As we know, there are a list of method and models like parametric (exp, ...
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1answer
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What is the current research on missing not at random data?

I have a data set with N ~ 5000 and about 1/2 missing on at least one important variable. Comparing the people with missing data to those with complete data it is fairly clear that the data are not ...
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Is there an R function to do a survival analysis with right censoring + nested + crossed factors

I have this dataset to model, but I'm not sure how to do it. I want to model the surviving probability of different populations of two species depending on a treatment applied. Populations should ...