Tagged Questions

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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Do we have a problem of “pity upvotes”?

I know, this may sound like it is off-topic, but hear me out. At Stack Overflow and here we get votes on posts, this is all stored in a tabular form. E.g.: post id voter id vote type ...
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Unbiased estimation of covariance matrix for multiply censored data

Chemical analyses of environmental samples are often censored below at reporting limits or various detection/quantitation limits. The latter can vary, usually in proportion to the values of other ...
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Informative censoring caused by cesarean section

I study labor and delivery as an epidemiologist. It is well established that a large fetus has a higher risk of causing maternal birth trauma. But a large baby is also likely to be delivered by ...
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Estimating a distribution from above/below observations

Let $P$ be an unknown distribution on $(-\infty,\infty)$. Let $X_1,\ldots,X_n$ be an iid sample from $P$. Let $c_1,\ldots,c_n\in(-\infty,\infty)$ be a known set of constants. We observe ...
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Censoring/Truncation in JAGS

I have a question on how to fit a censoring problem in JAGS. I observe a bivariate mixture normal where the X values have measurement error. I would like to model the true underlying 'means' of the ...
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How to fit a negative binomial distribution in R while incorporating censoring

I need to fit $Y_{ij} \sim NegBin(m_{ij},k)$, i.e. a negative binomial distribution to count data. However, the data I have observed are censored - I know the value of $y_{ij}$, but it could be more ...
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Imputation of a censored variable

I have a medical dataset with approx 200 variables. One of the variables is a bio-marker (concentration of a particular enzyme). It's distribution is right skew, and the problem is that values above a ...
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Joint pdf of a continuous and a discrete rv

Let us consider a manufacturing system. It involves 2 independent components. If one of these components fails then the entire system fails. Let $Y_j$ be distributed $\exp(Q_j)$ where $j=1, 2$. If ...
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How can I estimate the time at which 50% of a binomial variable will have transitioned?

I have the following data, representing the binary state of four subjects at four times, note that it is only possible for each subject to transition $0\to 1$ but not $1\to 0$: ...
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Averages of random subsets of variables

Consider data where each observation was generated as follows. We draw $Z_1,...,Z_m$ from some distribution. (Possibly they're independent or related in some other simple way.) Next, based on the ...
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How should I handle a left censored predictor variable in multiple regression?

I have a dataset (N=350) for which I would like to regress a neuropsychological test score (continuous) on age, education, symptom severity (continuous), and diagnosis (binary). Symptom severity is ...
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Get a desired percentage of censored observations in a simulation of Cox PH Model

This question comes from: How to simulate a Cox proportional hazards model with change point and code it in R (See answer) I want to generate a censoring variable $C=Exponential(\theta)$ that create ...
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Heckman selection model with difference-in-differences specification

Following my question on Tobit with DiD specification I am wondering if it is possible to estimate a heckman sample selection model with a Difference in Differences specification? For example in ...
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Simple case of MNAR missing data

I believe I have a very simple problem with missing data, but I'm a bit lost because all the materials I read seem to be focused on much more complicated cases. I have a random variable $X$ which has ...
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Survival analysis for nested, censored and dependent data

I have to analyse the effects of different treatments on the survival of individuals for 1 week. But: the data are 'grouped': individuals were grouped by 10, and the survival probability is ...
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Regression when your dependent variable is the difference between two doubly censored variables

Suppose you have a sample of $n$ outcomes and for subject $i$ you observe $Y_{i1}$ and $Y_{i2}$, which are 'before' and 'after' measurements on subject $i$. You have a single continuous independent ...
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Name of phenomenon on estimated CDF plots of censored data

My dataset contains two (rather strongly correlated) variables $t$ (runtime of algorithm) and $n$ (number of examined nodes, whatever). Both are strongly correlated by design, because the algorithm ...
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Analyzing categorical data where the last category is unbounded

This is a bit of a long-winded data vis question. We're gathering data from a water quality test measuring fecal contamination. The test measures fluorescence in 11 discrete chambers. The water is ...
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Right-censored survival fit with JAGS

Update: I got the JAGS model running and this eliminates the distracting part of my question. It's really about the proper preparation of data for dinterval() and inits. I can't find a concrete ...
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A random censored regression problem?

Assume I have random variables $X$ and $Y$. $X$ is observable; $Y$ is not. We also know that, if $X \leq Y$, $Z = f(X,Y)$ where $Z$ is a third random variable and $f(\cdot)$ is a known function; ...
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What is the magnitude of bias in censored regression when OLS is applied?

If my dataset comprises few censored variables (<1%) and I fit the OLS regression using a heteroscedastic resistant estimator (the residuals are not terribly heteroscedastic to begin with)- are the ...
I want to be able to calculate the distribution of $$Y = \sum_{i=1}^n\max\{0,X_i\}$$ where the random variable $X_i\sim N(\mu_i,\sigma_i)$. Is the calculation of $f_Y(y)$ possible and if so what is ...