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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107 views

Is data censored if it's “still alive”?

Let's say I'm observing the mortality of flies. Say I have 100 flies that are born throughout the year. And also say I am recording the alive/dead status of a fly every single day, without fail. So ...
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1answer
300 views

Mean of a censored Poisson random variable

Consider a real demand estimation problem of a retailer where matrix $Y$ (contains Poisson random variables) is the real demand and its mean need to be estimated by using sales data (matrix) $X$ which ...
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1answer
135 views

Help with Right Censoring for survival analysis

Hi all I would like to do some survival analysis. The most difficult part for me is setting up the censoring data correctly and I would appreciated if someone can help confirm if I'm doing this ...
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96 views

Estimator of (left-)censored normal distribution when mean>>std

Suppose there is a left-censored normal distribution, and we know there is a total of $m$ samples, for which we know $n$ of them. I am trying to estimate the mean and variance of the underlying normal ...
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224 views

What is the distribution of min{0,X} when X follows some general normal distribution?

What is the distribution of $\min\{0, X\}$ when $X$ follows some general normal distribution?
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1answer
69 views

Linear regression: how to treat an explanatory variable that is discrete but does not have a natural zero

Background/study system: One of my MS students is studying the biomechanics of strand breakage in Spanish moss (an epiphyte--or plant that lives on other plants). Spanish moss has strands that can ...
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1answer
36 views

Calculating censoring proportion in recurrent event time data

My question pertains to how to calculate censoring proportion in the perspective of recurrent event data in which an individual subject can have multiple survival times related to repeated occurrences ...
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0answers
71 views

Survival model - sample with only censored observations

I have a question related to survival models: for instance, the survival probability of people that have a disease. In all examples I've seen so far, the data used to estimate those models sometimes ...
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1answer
36 views

survival analysis with varying follow-up time

I have a retrospectively enrolled cohort of patients with aortic disease. The endpoint is aortic enlargement at or after postoperative 6 months. Patients experiencing aortic enlargement within 6 ...
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Estimate the conditional probability given contaminated output?

I have a dataset with exam grades and for each student an indicator variable that is equal to $y=1$ if the student was cribbing and $y=0$ otherwise. As a result of the crib the grade is expected to be ...
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1answer
551 views

Fitting distributions on censored data

My question deals with fitting distributions on censored data; for the purposes of clarity, we can consider a continuous distribution which is both left and right-censored. In such a case, the ...
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148 views

How to fit a (gaussian) mixture model to a dataset with (right) censored data in R?

I am trying to fit a mixture distribution to a dataset in R. Exploiting the R package mixtools, this goes pretty well. However, up to 20% of the data point in the dataset are right censored, therefore ...
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1answer
49 views

Censored regression methods for analyzing extreme end of a normally-distributed variable

I have a normally distributed continuous variable referring to an observed human behavior, and I'm interested in measuring or rather analyzing the extreme of this behavior, namely, the top 10% of the ...
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68 views

Which duration model to use with a fully right censored database

Currently I'm examining the duration of residence of households. I have a database at my disposal that indicates how long a specific household resides in its current home. I want to explain their ...
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64 views

Continuous or categorical data. Modeling depth, that is continuous through a range of values, but has a max depth that is discrete

I'm modeling depth to bedrock. These data are continuous through a range of depths, but have a max value that equates to as far as we could dig with our soil auger. So they are continuous through a ...
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1answer
407 views

How to model left-censored and right-truncated data on Stata? [closed]

I have data that is left-censored and right-truncated. I'd like to run a tobit or truncreg. Although, using ...
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173 views

Residual Useful Life estimation from multivariate time series with lots of missing data and censoring, using neural networks

I have a set of industrial machines, for which I collect measurements from a few sensors (say, $d=20$) in time. So I have a $d-$variate time series for each machine. Let $t=0$ denote the start of my ...
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31 views

How can we deal with limit of detection independent variables in regression

Suppose that you have a regression in which one or more of the independent variables has a lower limit of detection (e.g. some result of blood tests). How best to deal with this? Any pointers to the ...
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12 views

Proper way to assess median failure distance in the presence of censoring

I would like to measure the median distance at which a material fails when it is stretched. At first pass, this sounds trivial and there is a simple version of this by which I pull a material until ...
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1k views

How do left-censored data and right-censored data impact Cox Regression?

My application is not a traditional survival analysis scenario. However, I believe survival analysis methods, e.g., Cox regression, can be a possible solution. In particular, my dataset contains two ...
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34 views

Right-censored predictor where censorship means “never”

My major predictor is "time to consultation" (of the specialist), which ranges from 0 to roughly 72 hours. There are also patients in this group whose value is "never". That is the procedure in ...
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1answer
127 views

How to deal with different likelihood of censoring across groups in survival analysis?

I am analysing survival data for nematode worms fed on four different bacterial diets (four groups). Each group has at least 70 events (deaths), but there is often a very uneven proportion of ...
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1answer
230 views

Learning a continuous model from binned data

A very similar question has been asked before, but it didn't get a real answer. Background I would like to develop a probability model for a continuous, ratio-scale random variable $Y$. Let's say it ...
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113 views

Likelihood with random censoring

Suppose to observe a random sample from a r.v. $Y_i=\min(T_i,C_i)$ where $T$ and $C$ are iid absolutely continuous distribution. I would like to inference about a parameter of $T$ (for example, $\...
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1k views

How to compute MLE for Pareto distribution data with right censored observation by using R programming?

I am doing survival analysis and writing codes to compute MLE for several distributions. Yet, I get stuck while writing for Pareto distribution with right censored observation. For complete/...
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942 views

What is the relationship between Cox regression and Tobit regression?

To handle censored data, I see that some researchers use censored regression methods, like Tobit regression, some use classic survival analysis models, like Cox regression. I know that Cox regression ...
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2answers
752 views

Finding the mean of right-censored values

I wanted to check how fast an average colleague of mine is able to complete a puzzle, so I ran some experiments. The problem is they weren't done in exactly 50 minutes, I always got bored and moved on ...
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1answer
2k views

Best way to handle na values in regression predictor variable

I am running a multinomial logistic regression model in R (using the multinom function from the nnet package) with a set of 12 ...
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1answer
66 views

How to handle non-detects in duplicate samples

I took two separate water samples (one sample per bottle) in twenty one river locations (n=42). For the purpose of this question I am calling the two bottles duplicates. I am trying to show how ...
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1answer
303 views

How to fit gamma distribution to events not happen? [duplicate]

I am trying to fit a gamma distribution to the failure time of a kind of bulb. I have 40 data. However only half of them are actually the failure time. The result 20 are times those bulbs being used (...
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59 views

Can you recover regression coefficients from quantile regression coefficients on censored data?

Suppose you have data that you know to be well-fit by a GLM with a specified link and variance function. You would like to estimate that model. However, you do not have access to the data; instead, ...
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77 views

Appropriate loss function for unobservable failure time

I'm trying to construct a forecast for the failure time of a system. I have a model for this failure time built from physical understanding of the system. I'd like to be able to quantify the accuracy ...
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1answer
337 views

What are the mean and variance of a 0-censored multivariate normal?

Let $Z \sim \mathcal N(\mu, \Sigma)$ be in $\mathbb R^d$. What are the mean and covariance matrix of $Z_+ = \max(0, Z)$ (with the max computed elementwise)? This comes up e.g. because, if we use the ...
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100 views

what is a censoring hazard ratio?

I saw the following expression in paper [1] (equation 1) \begin{equation} \Pi_{i=1}^{n} \left[\frac{HR(t_i,x_{\sigma(i)})}{\sum_{j=1}^{n}Y_j(t_i)HR(t_i,x_{j})}\right]^{\delta_i}\left[\frac{HR^C(t_i,...
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249 views

simulation of non-homogeneous poisson processes

When simulating non-homogeneous (time-dependent hazard $\lambda(t)$) Poisson processes, we can use thinning [1] to generate jump times $t \in [0,t^0]$: initialize $t = 0$ generate $u_1 \stackrel{d}{\...
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184 views

Principal component analysis with censored data

I would like to estimate an underlying linear relationship between two variables x and y. There is significant error in both the x and y measurements, making linear regression inappropriate. However, ...
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2answers
70 views

How do you account for suppressed values in a time series regression?

I'm analysing time series data of monthly traffic fatalities in several US states, but have come upon a problem with suppressed values. The data come from CDC WONDER, and cells with any value less ...
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1answer
3k views

Fit a Weibull distribution to…right-censored data?

Premise: I know next to nothing about survival analysis, I just started. I have a vector of failure times for some machines. Most of the machines (3362 vs 2694) are still running today, so I know they ...
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1answer
793 views

Handling null values in linear regression, which are suppose to be higher than the non-null values

I am currently doing a linear regression, where i try to predict the housing prices based on different variables that describe the house's spatial features (such as the distance to the closest city, ...
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150 views

Censoring in survival analysis - when should I be concerned that too many patients are censored?

I review a lot of papers using observational datasets (think large secondary national databases) and many report survival. Risk tables often show substantial censoring (e.g. out of 10,000 patients, ...
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1answer
304 views

Truncated/Censored Regression in the Multivariate Normal Case

Assume that a $n$-dimensional vector of real valued variables $\mathbf{Y}=(Y_1,...,Y_n)^T$ is given. We know that they are jointly normal which expectation vector $\boldsymbol{\mu}=(\mu_1,...,\mu_n)^T$...
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3answers
152 views

Methods for censored covariates

I am facing the situation that I have different data sources that in principle it makes sense to combine. The outcome (independent) variable is defined the same way, but the (likely) most important ...
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86 views

Right, Left, Interval, Delayed, and truncted data

I have a medical data set that has all the following cases: Right-censored Left-censored ...
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32 views

Censoring based on dependent variables of other subjects

I understand that the Heckman approach can be used if the observation rule is static and thus can be estimated easily. However, I have a panel where simply the largest $y$ among all individuals in ...
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1answer
493 views

Censored Logistic Regression?

I'm trying to run a logistic regression with a dependent variable $y \in \{0,1\}$ and one independent variable $x$. I'm trying to find the coefficient $\beta$ in the equation $Prob(y=1)=\frac{e^{\...
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24 views

Censoring or Measurement Error?

I have a satellite-recorded variable $X_{it}$ that is supposed to act as a proxy for some socio-economic variable $Y_{it}$. However, due to limitations of the recording device, $X_{it}$ is censored ...
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1answer
128 views

Two types of left censoring in a time-to-event model

I have (population) survey data where I know one of three things about each respondent's experience of an event (A): The event A occurred at an age specified by the respondent. The event A is a ...
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1answer
101 views

Survival analysis: Excluding cases of trivial follow-up time?

I am finishing up the data collection for my retrospective cohort study, which I have designed with the intention of conducting survival analysis. Our outcomes of interest are recurrence, metastasis, ...
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213 views

How to compare values between groups if data is left censored

Data I have a measurement with a detection threshold. I can see that one group has more succesfull measurements (larger number) and also have more higher measurements (longer tail). Comparing the ...
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40 views

MCMC for model with cumulative hazard involving integrals?

Let $h(t\vert \theta, x)$ be a hazard function with parameter vector $\theta$ and covariate vector $x$, and let $H(t\vert \theta, x) = \int_0^t h(s\vert \theta, x)ds$ be the corresponding cumulative ...

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