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.

learn more… | top users | synonyms

0
votes
0answers
10 views

Right & Left data censoring

I have question regarding Data Censoring Methods. Is there any link where I can find details about Left and Right Censoring? Also does anyone have any clue of Articles where someone tried to merge ...
1
vote
0answers
14 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 ...
0
votes
0answers
15 views

Random right cenoring

I observe a series of values from different trials ($Y_1, ... Y_N$). All values come from the same distribution ($F(\cdot)$). Trials do not have the same number of values ($N$ differs across ...
3
votes
2answers
69 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 ...
1
vote
0answers
16 views

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?
0
votes
1answer
41 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 ...
1
vote
0answers
22 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)= ...
1
vote
0answers
19 views

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 ...
0
votes
1answer
29 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 ...
0
votes
1answer
37 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 ...
0
votes
0answers
13 views

to estimate bj regression category by category

I'm studying linear regression model with censored data. ~ Buckley James Estimator. For example, I have a data set which contains groups (two categories; 1,2). I estimated bj regression category by ...
0
votes
0answers
19 views

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 ...
1
vote
0answers
17 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 ...
3
votes
0answers
38 views

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 ...
3
votes
1answer
31 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 ...
3
votes
0answers
44 views

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 ...
3
votes
2answers
98 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?
1
vote
1answer
20 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 ...
2
votes
1answer
45 views

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 ...
7
votes
2answers
246 views

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 ...
0
votes
0answers
19 views

Survival analysis: how are censored and non-censored patients dealt with and defined?

I have a pretty simple question. In a paper I am revising for a journal, there is a small survival analysis of patients. The study period starts on 1 March 2010 and ends on 1 June 2015. There are 70 ...
5
votes
0answers
26 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 ...
4
votes
1answer
26 views

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 ...
0
votes
0answers
32 views

Need the formula and to understand the number needed to treat

I am reading the article http://www.ncbi.nlm.nih.gov/pubmed/16214598. I am having trouble with the calculation formula (to test it / reproduce it). The relevant information is in page 1282. For those ...
1
vote
0answers
14 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 ...
0
votes
0answers
22 views

Right censored data, abundant in zeros for regression analysis

I am looking at conditioning to stimuli and there in the time taken to perform a certain task. The IV for this data is Conditioning periods ranging from 1-34 periods and the DV is the time taken for ...
0
votes
1answer
45 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. ...
1
vote
0answers
47 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.... ...
1
vote
0answers
10 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 ...
2
votes
0answers
47 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 ...
0
votes
0answers
59 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 ...
0
votes
0answers
16 views

competitive risk in propensity score matched cox regression

I am actually performing a survival analyse using propensity score matched cox regression. My outcome is calculated from biological data contained in a database. I censured each patient at the time ...
0
votes
1answer
30 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 ...
0
votes
0answers
16 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 ...
0
votes
1answer
27 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. ...
1
vote
0answers
20 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 ...
1
vote
2answers
41 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 ...
2
votes
2answers
49 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 ...
0
votes
1answer
24 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.
0
votes
0answers
14 views

Does RMSE accurately represent performance for censored data?

I am working with some remotely sensed data collected at irregular intervals and want to use these observations to evaluate performance of a model. For each site location I have about 4-9 ground truth ...
2
votes
1answer
98 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 ...
0
votes
1answer
50 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 ...
0
votes
0answers
27 views

Data censorship - simple reconstruction of missing data?

I have data from disease symptoms assessment on individuals (over time). Pattern of the disease is always a decreasing sigmoid, the disease starts with a 100% sound tissues, but ends up with a 0% ...
1
vote
1answer
17 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 ...
0
votes
0answers
11 views

Handling a censored factor score?

I have an 11 item measure for which I am computing factor scores. It is a censored (floor effect) measure. EFA/CFA analysis indicates I should remove 3 of those items. Whether or not I remove those ...
4
votes
2answers
88 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, ...
0
votes
0answers
69 views

WinBUGS - sample from the posterior of exponential distributed survival times

as introduction to WinBUGS, I want to simulate the posterior of the Gamma-Exp-Model. Because the posterior is known, I can varify the result. But the true posterior is always shifted to the right. I ...
1
vote
0answers
57 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 ...
2
votes
0answers
40 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 ...
1
vote
0answers
161 views

How to estimate mean and variance of censored normal?

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?