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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95 views

right or interval censored survival curve for survival within a survey period

I was hoping somebody could help with a relatively easy survival analysis question. I have survey data of an animal populaton and I want to create a survival curve for a specific year. So, I have ...
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420 views

Estimating a rate of failure/survival using only right censored data?

I am trying to estimate the probability $q$ that a household with certain known covariates will move to a new home in the following year, by estimating an event rate $\lambda$ dependending on some ...
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Need help understand likelihood in survival analysis

I really appreciate it if you could help me understand the likelihood in a survival model with a time varying covariate. To be more clear, let's first start with a survival analysis with fixed ...
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566 views

Maximum likelihood of gaussian with right censoring

I'm trying to fit the mean $\mu$ of right-censored gaussian data ($n$ samples) in a toy example (let's assume $\sigma^2=1$ is known), and the censoring happens always at the same value $s$. As far as ...
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1answer
460 views

Poisson regression for ordered variables

I have three waves of data, and I am trying to estimate group-based trajectories of binge drinking across the three waves. The question asked (at all three waves was): “Over/During the past 12 months, ...
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1answer
38 views

Fitting and comparing distributions based on diverse summary statistics

I have a bunch of samples, about 35, drawn from a fat-tailed distribution. I think it is reasonable to assume that the samples are all drawn from distributions from the same distributional family, ...
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24 views

Combining monthly distributions of data with different right-censoring levels for prediction

I have a number of pricing datasets with integer values (prices in round dollars) for the same product which are right-censored at different levels (one level per dataset). I would like to combine ...
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2answers
6k views

What to do with data that are bimodal at two tails of the distribution?

I am in a weird position where I prespecified a plan to use linear regression to analyze my data, and stated I would use transformations to address any assumption violations. I'm pretty certain my ...
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How to fit a distribution of censored data? [duplicate]

I have a right censored data set and want to fit a distribution to my observations. How does maximum likelihood estimation work on censored data and are there any issues that I need to consider?
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663 views

Survival analysis with multiple factors

I want to do survival analysis in a situation where I expect the survival time depends on two factors: Environment. Each person is in one of three environments, $E_1,E_2,E_3$. I expect that the ...
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698 views

Variance-Covariance matrix of Weibull Distribution for right-censored data

The probability distribution function, cumulative distribution function and survival function of Weibull distribution are given by respectively, \begin{equation} f(t;\alpha, \beta)= \dfrac{\beta}{\...
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how to quantify variation in continuous outcome for samples matched on continuous predictor

I have a data consisting of about 2 million cases. Cases are scored on some (overdispersed) predictor we'll call "employee performance." I would like to match or pool cases with the same score or ...
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1answer
279 views

Version of Mann-Whitney U test, for right-censored data

Is there an equivalent of the Mann-Whitney U test, but for right-censored data? I have right-censored numerical data from two different groups. The mean for one group is higher than the other. I'd ...
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70 views

Inventory Turnover Estimation

I have an inventory of real estate. Every period I am acquiring some new inventory and selling some items from the inventory. I would like to estimate the average waiting time it takes to sell an ...
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Survival estimation goes crazy when I move all censored times to t=0

I have a simulated dataset with 1000 observations and Weibull-distributed survival time as outcome. A certain percentage $p_1$ of these guys belong to a risk group ($Z_i=1$ for risk group, $Z_i=0$ for ...
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33 views

Censored items in FERPA-compliant education data

I have open source data for K-12 educational performance. It is for North Carolina, at the individual school and subject level. It is conformant with FERPA regs, leading to my problem. It reports ...
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Sign and size of OLS bias for Tobit models

I have a question related to the sign and size of the OLS bias in the case of a Tobit model. Consider the following model (1) Sample of observations $\{X_i,Y_i\}_{i=1}^n$, i.i.d., $X_i$ is a vector ...
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224 views

Derivation of the censoring likelihood function? [duplicate]

The (right-) censoring of likelihood function is defined as: $$ L(\theta) = \prod_{i=1}^m f(x_i;\theta) \cdot \prod_{i=m+1}^n P_{\theta}(X_j>a) $$ where observations $x_i$, $i=1,...,m$ have ...
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Likelihood function for a Weibull model

I have an assignment for my course Microeconometrics. Currently I am stuck on the following question You are asked to help out with the statistics of a medical study. We are interested in the time ...
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2answers
671 views

Meaning of “missing by design” in longitudinal studies

I'm French and I'm reading an English book. I don't understand the term "when missingness is by design" — what does "by design" mean?
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277 views

non-parametric trend analysis with data that is both left and right censored

I am assessing the the presence of monotonic temporal trends in E. coli concentration data using a non-parametric approach. These data are both right and left censored (for example the lower detection ...
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1answer
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Can a Cox proportional hazards model be used on general left-censored data (i.e. non-survival data)?

A familiar problem in applied science is having censored data, in particular left-censored data arising due to an assay or piece of equipment having a lower limit of detection (LOD). Assuming a ...
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Layman's explanation of censoring in survival analysis

I have read about what censoring is and how it needs to be accounted for in survival analysis but I would like to hear a less mathematical definition of it and a more intuitive definition (pictures ...
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How to get R squared/goodness of fit for Tobit model in R?

I do a Tobit regression to analyze censored data. To measure the goodness of fit the authors of these papers use Efron's $R^2$. So my idea is to use this one as well. To realize my Tobit regression, ...
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127 views

KDE for censored data

I have a sample of observations where about $30\%$ of the observations are right-censored. I want to fit a kernel density estimator to this sample but I have not found a standard method to do so. Is ...
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1answer
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How do I compute an average when one of the measurements couldn't be measured?

In my biology class we were doing a lab on respiration rates of peas. We used a respirometer with a small pipet tube (markings up to 1 mL) to measure the volume of gas; by immersing in water, the gas ...
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31 views

Treatment of waiting time data with repeated observations for a finite time

A call center is open for 9 hours every day. My data are the times of occurrence of calls, divided in days. Some days are busier than the others and some days no calls at all occur. I have to estimate ...
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1answer
2k views

Dealing with Right Censored Data

I'm working with a dataset with n of roughly 300,000 and am trying to build a model to predict the time-to-event from multiple explanatory variables, including past times from the same subjects. ...
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262 views

Expected value of a censored poisson

I have the following density (it's a censored model): $$f(y) = \begin{cases} e^{-\lambda}(1+\lambda), & \text{if }y^*=0,1 \\ \frac{\lambda^{y^*}e^{-\lambda}}{y^*!}, & \text{if }y^*=2,3.... \...
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65 views

Uneven (right) censoring where the time of truncation is constant

I've collected data comparing the relative success of two different groups of participants on finding the answer to a difficult question. The problem is that not all the participants in the control ...
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616 views

Right-censored independent variable in Cox/logistic regression

I have a right-censored continuous independent variable that I want to include in a Cox regression. The variable is a physiologic test which is capped at a certain time, say 120 seconds, due to safety ...
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1answer
288 views

Censored Data Log Likelihood

Suppose we have a n random samples ($X_1,..., X_n$) from a negative exponential distribution. If lets say we have these n random samples are censored at t, such that ($X_1, ..., X_m$) are observed and ...
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1answer
47 views

censoring as a result of survey screening question

I have a survey data where respondents were asked if they or an immediate family member had previously used a lawyer and, for those who said yes, they were then asked if they had ever sued. I want to ...
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24 views

Censoring for events that don't occur

I have data on when the time between two events A and B. However, I am assuming if the time between them is more than 5 hours then the two events are unrelated and so we assume that on these occasions ...
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1answer
192 views

Counting total number of cells producing antibody in a 96-well plate using Poisson

I make cells produce an antibody. I then add cells to plates that contain 96 wells (random distribution). I know a cell is in a particular well because the well will be positive for the antibody. ...
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69 views

How to find the expected value of a random variable when it is observed only in a range?

I want to estimate an average livespan of a user account which is a time-difference in days between the account open and account closed. I observe the livespan of accounts that were closed before the ...
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1answer
1k views

Fit a censored log-normal distribution to data using MLE

I have some data for numbers that are positive and these numbers are capped above at C (so if a sample from my data should have exceeded C, the data generating process will simply return C). I know ...
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2answers
109 views

How are censorings before the first event dealt with in survival analysis

If you have a dataset, sorted into ascending order by survival time (minimum of censoring and event time), and this dataset contains at least one censoring before the first event (so that the start of ...
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2answers
61 views

Inference for a distribution with different number of samples due to censoring

I have the following problem in case someone has an idea about how to solve this. Assume three experiments that refer to the same population for a random variable $X$. In the first experiment, I ...
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1answer
34 views

What is the justification? [duplicate]

I understand 'when' we right censore a survival time. But why do we do so? And how does it affect analysis in survival context. I would appreciate it anyone could recommend some reference.
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121 views

Probability density problem

Suppose that the random variable $X$ is uniformly distributed on the interval $[0,1]$ (i.e. $X \sim U(0,1)$) and suppose that $$Z=min(2,2X^2+1)$$ (a) Explain why $Z$ does not have a density ...
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1answer
94 views

Handling survival data where people join at various stages

My question is about survival analysis. According to this censoring is a condition in which the value of a measurement or observation is only partially known. For example, suppose a study is ...
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1answer
31 views

How to average days until completion when some items haven't completed the cycle?

I am attempting to calculate the average number of days it takes for an order to go through our process - from receipt of order to delivery. When calculating the average days, how should I handle ...
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2answers
165 views

Should one use a censored survival model when an event is only observed at death?

A colleague of mine is trying to estimate how neutron radiation exposure changes cancer incidence rates (in mice). He has autopsy data that reports whether a cancer was observed at the time of death, ...
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501 views

Handling Informative Censoring in Survival Analysis

In a survival study with informative censoring (for example, studying the effects of cigarettes on mortality and smokers are more likely to be Lost to Follow Up). This causes the censored data to be ...
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0answers
289 views

Kernel density estimation with censored data

I have several univariate data sets that I would like to fit with a Kernel density estimator. However, some of the data sets contain left, interval, and right censored observations. How can I ...
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0answers
757 views

How to estimate mean and variance of censored normal? [duplicate]

Supposing I have data which I know is normally distributed, but because the recording process is right censored, how do I estimate the parameters of the distribution?
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1answer
173 views

Censoring “Death” in Time-To-Recovery Analysis

I am performing time-to-recovery analysis comparing 2 groups. In both groups, a few subjects died from the disease under consideration (instead of recovering). Is it appropriate to consider the deaths ...
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533 views

How to simulate informative censoring in a Cox PH model?

I wish to simulate events from a Cox PH model where the censoring is informative, and to compare parameter estimator quality with estimates obtained from data generated by a Cox PH model with non-...
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149 views

simulate censored data (right censored) using R statistics [duplicate]

I want to generate right censored data, but I want to be able to pass in a parameter to a function to dictate that a certain percentage of the data will be censored. I have found this R-package: http:...

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