Questions tagged [censoring]

The process of censoring yields data w/ only partial information. The most common example of censoring is *right censoring* in survival analysis, where the time until the event occurred is only known to be longer than some duration because the event had not occurred when the study ended.

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30 views

Bootstrap for Performance CI with Imputation and Train/Test Split

I am currently performing an analysis in which we are hoping to develop a risk score for a survival outcome using machine learning techniques. Currently, our process is as follows: Split randomly ...
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Difference in fitting to right censored data between MLE and Bayesian method

I am fitting a Weibull curve to right censored data. I am doing it by general MLE method using Survival::survreg() as well as Bayesian method using brms::brm. I am pretty sure that I am getting the ...
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Should "rake throw" data be treated as binary, Poisson, interval-censored, ordinal, or...?

I'm currently analyzing "rake throw" data (see here for details), which are a type of data I'm not as familiar with. The gist is that aquatic plant presence and abundance are often estimated ...
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91 views

Doing MLE when data is missing not at random

Suppose $X, Y, S$, and $Y=f_\theta(X), S=f_\phi(Y), S \in \{0,1\}$. For $n$ data samples, the $y_i$ is only observed for those who have $s_i=1$. That is, we have $\{x_i, y_i, s_i=1\}_{i=1}^{l}$ and $\{...
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Sum of Equally Interval Censored Normal Random Variables

Suppose a standard normal random variable $Z\sim N(0,1)$ is interval censored at $[-a,a]$, $a >0$, so that the new censored variate $x$ is $$ x = \begin{cases} -a &z\leq-a \\ z & -a< z&...
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Calculating number at risk for Kaplan Meier analysis with staggered entry

I am trying to create KM curves in r on data from a telemetry project. The data is right censored and additionally not all individuals were tagged on the same day so they entered the study at ...
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22 views

Baseline adjustment when both pre- and post values are subject to left-censoring

Assume $X$ is a binary treatment variable, $Y$ is a continuous variable measured pre- and post-treatment $(Y_{pre}$, $Y_{post})$, and $Z$ represents the remaining covariates. Both $Y_{pre}$ and $Y_{...
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24 views

Censoring for a compount event

I have a data set consisting of patients undergoing a treatment. The data set contains treatment start date, treatment end date, and date of death (if the patient has died). I also have a set of ...
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Survival analysis: informative right censored data question

I am attempting to analyze data for someone and am getting stuck on finding something that is appropriate. The design of the experiment is as follows: vials are set up with 10 flies per vial (either ...
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Statistical analysis on values that are not exact but above or below a limit (e.g. >100, or <5)

I have a data set with a small number of bioreplicates (3-10) per sample, and I am assessing whether each sample is statistically different from the wildtype control using a Kruskal-Wallis test with ...
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How to test censoring patterns of two samples agree?

I am not sure I even understood the book. I am reading Applied Survival Analysis by Hosmer, Lemeshow and May's pg 58. The book says "Problems in study design and data collection can lead to ...
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Left censoring with time-varying covariates

I have a data with some participants entering the study with a disease of interest already present. For others, I have several points of observation where different factors were measured (such as ...
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Survival Analysis: samples with starting times before the data started being recorded

Summarize the problem: I'm working on a problem to estimate customer life time for our subscription-based business model. My data contains all purchase transactions between 2015-01-01 and 2020-12-31. ...
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1answer
35 views

Constructing hazard for x-year survival in cox models

If a person wants to assess the 1,5, or 10 year survival of a group of patients how should they consider right censoring for the patients? Between these 2 options what would be best for this 5 year ...
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Response variable suffers from both left censoring and MAR

I have a large water chemistry dataset where my response variable (radium-226 concentration) has two types of missing data. Sometimes it is left censored, sometimes the value is reported, but most ...
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Extreme Value Analysis of Hurricane wind speeds

As per the theory, an EVA with annual maxima presupposes that the series is complete, i.e. all years have an event. However, hurricanes don't occur every year, and so the hurricane wind speeds in ...
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Dealing with left-, right- and interval-censoring and left- and right-truncation

I have a survival data set with left-, right- and interval-censoring and left- and right-truncation. Now I want to fit a Cox proportional hazard and an AFT model to these data. What is the best way to ...
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How to get main effects (deviance table) on the censored quantile regression in R quantreg::crq?

I know it's about R, but it's anyway a statistical question. I want to calculate confidence intervals for the survival quantiles (median and the 1st quartile). I was asked to use namely the censored ...
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39 views

Restricted mean survival time per patient

Apologies for the basic question (I have a clinical training background therefore am not so experienced on the stats front). Is it possible to calculate the restricted mean survival time for each ...
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Estimating summary statistics (Median, 10th, 20th, 30th, 40th percentile and 95%CI ) when censoring exceeds 80%

I am trying to determine the population median, 10th, 20th, 30th, and 40th percentiles (+/- 95%CI) based on 71 samples of sediment total DDT(ug/Kg). Those data that I am using have 71 observations ...
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70 views

Proportional Hazards Model and EM Algorithm

I am working with the standard proportional hazards model given by $\lambda(t|Z) = \lambda_0(t)e^{Z\beta}$ for a special type of data that requires an EM algorithm to estimate a discretized version of ...
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How can I deal with left censoring on continuous outcome variables

I have a Y variable that is long term (ex: profit in the next 12 months). This means that I only fully observe Y only in cohorts that are at least 12 months old, but I can partially observe it in the ...
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Given median survival and CI, and assuming an exponential distribution, can one predict survival and CI at a time point?

I have access to a manuscript where the median survival and CI are reported. The shape of the curve approximately takes the shape expected for an exponential distributed failure time. I don't know the ...
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OLS regression when dependent variable's measurement is capped

Let's say you have $y=a+xb$ but your $y$ variable is measured imperfectly such that the measurement never exceeds 99 but in reality it should. We know it's a measurement issue. Is the best technique ...
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Is it possible to test what is the type of censoring (or if it is informative/non-informative/etc) when doing survival analysis?

(considering right-censoring) Without knowing the experimental design, is there any conclusion/idea about the type of censoring I have just with the data? I was googling and looking around in ...
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How to model censored and clustered data?

Mixed models can be used to handle clustered data. TOPIT models can be used to handle censored data. I am dealing with a dataset that are both censored and clustered. is there any modeling techniques ...
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How to fit Censored least absolute deviations (censored LAD) in SAS?

Censored least absolute deviations (censored LAD). Censored LAD, proposed by Powell, is a robust alternative to maximum likelihood estimation for the Tobit model. Powell J. Least absolute ...
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218 views

How to simulate survival data with censoring using R

I want to simulate survival data with a sample size of N=100, which follows the Weibull distribution with proportional hazards and constant baseline hazard. Two correlated covariates, which follow ...
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24 views

average event time if event did not occur to everyone

How to determine the average or expected time duration of an event to a group statistically correct, if this event has not happened to everybody yet? One could consider only those to whom the event ...
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What model do I use if I have two response variables which are influenced by each other?

I conducted an experiment where I looked at measuring animals performance for a certain task. I have 2 response variables 1.success/failure at performing the task (bionomial); and 2. latency (time) to ...
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43 views

Right censoring with recurrent events

I am dealing with retrospective survival data covering 60 years. Some people start their first spell in 1960, others start their first spell in 2000 (they are never left truncated). People can ...
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35 views

What regression approach would suit zero-inflated data that is censored at a fuzzy threshold?

Monthly grid-cell burned area estimates are (almost) lognormally distributed, censored at a fuzzy threshold and zero-inflated. I want to predict burned area from weather etc. About 40% of the ...
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Survival Analysis for Attrition Study and Informative Censoring

I am trying to develop a model to understand attrition among students. Apart from binary classification, I am thinking of performing a survival analysis by following the students for 3 years at the ...
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98 views

How can I fit a regression for a variable which have a maximum value?

Let's suppose I have a test which gives me the dosage of an analytic in the blood. The results of the assay are in a range of 0 and 1000; all subjects who have a value higher than 1000 will be ...
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160 views

Estimator of a censored exponential

I am trying to self-study the MIT OpenCourseware course on Statistics, here: https://ocw.mit.edu/courses/mathematics/18-650-statistics-for-applications-fall-2016/syllabus/ On problem set 4, question 3 ...
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Aggregating (taking the mean of) a censored variable

This post is related to this post. I have survey data, with a (censored) range from 0-100, that looks as follows: ...
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Can you have "missing" predictors in Cox regression or are these just considered [right] censored data?

If data is extracted from electronic health records and used for survival analysis, can outcome vars be considered missing or are they just considered right censored data points?
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Survival analysis to estimate kanban tasks completion times

I am working on a problem to estimate task completion time in kanban (project management tool). While doing EDA, I looked at tasks that are either done or cancelled. In this case, I defined the ...
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2answers
49 views

R: Left-censoring a probablity distribution function

I would like to left-censor (at zero) a probablity distribution function, but I just can't find a way to implement this in R. I have reviewed previous questions about censoring, but none have provided ...
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Modelling Task Completion Data

I have a two dimensional dataset - the first variable ($t$) represents time, and the second ($y$) is bounded between 0 and 1: Think of $y$ as percentage completion of a task. $y$ is dependent on $t$ -...
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72 views

Intuition behind Brier score weighing step for censored data

Sources seem to suggest that when calculating Brier scores involving right-censored data, one must weigh the otherwise mean square error function with the inverse probability of censoring weights ...
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1answer
47 views

Survival Analysis - Right Censoring Data

I am using Survival Analysis to build an attrition model. I have a data set with ~15,000 people that spans the past 5 years. Approx. 2,000 left in the last 5 years. The remaining people stayed at the ...
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34 views

Sampling censored empirical distribution

I have a dataset with lifetime values that is right-censored. My goal is to estimate the lifetimes of all items in the set that are censored. Here is what I did so far: Use Kaplan-Meier to build the ...
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1answer
215 views

Estimating long-term side effects of Covid vaccines in short time (statistical design of clinical trials)

I am interested in statistical procedures and study designs used to determine the absence/acceptability of long-term side effects of covid vaccines. Given that these vaccines were created and approved ...
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37 views

Bootstrapping to address interval censored data

I am trying to run a cox proportional hazards model on data that is interval-censored (and I guess right censored). Within this model, I believe one of my covariates' relationship should be modeled ...
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679 views

Misconception about left censoring

While trying to learn about censoring, I stumbled across a sentence on Wikipedia which I do not understand: A common misconception with time interval data is to class as left censored intervals where ...
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Transforming a right-skewed continuous response variable to an ordinal one: is this dumb?

I am estimating task time-to-completion using a sample size of ~36k. ~34k points are complete, ~2k are not. The response variable for my sample is right-skewed. I want to use this data to predict how ...
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Right censoring treatments: complete case, MICE and IPW <Pros and Cons>

I have always been a bit unsure about how to deal with right-censored data. From my experience, most clinical researchers around me prefer to use complete case analysis to treat right-censored data, ...
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19 views

Test if a sample comes from a theoretical distribution (with a specific type of censoring)

My situation is the following. I am estimating certain numbers from a dataset split in $n$ parts, one number for each part. How and why exactly is not relevant to the current question, but as a toy ...
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55 views

Question about the effect of administrative censoring time point on survival analysis

Imagine a simple Kaplan-Meier analysis where administrative censoring is applied at time=5 years. In other words, I may have follow-up data on persons out further but i am choosing to censor them at 5 ...

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