The Kaplan-Meier curve plot is one example, and it works in perfect harmony and synchronization with all other plot types, such as heatmap, Venn, PCA, box, bar, genome, and scatter plots. It is straightforward to configure the Kaplan Meier plot for a layout that will meet your requirements and those of a potential reviewer Logrank test for comparison of survival curves ; Logrank test for trend ; Hazard ratio . Graphs. Kaplan Meier survival curves: Survival curves with 95% CI: Survival curves with numbers at risk table: Links. Download free trial. Kaplan Meier Survival Curves section of the MedCalc manual
Draws the Kaplan-Meier curve with confidence interval, calculates the Log-Rank p-value, power, effect. Draws distribution chart and a histogram. Kaplan Meier Survival Analysis. Draws the Kaplan-Meier plot and calculates the log-rank test (log rank test is only for two group). Video Chi-Square calculator Goodness of fit calculator. Test. Kaplan-Meier analysis allows you to quickly obtain a population survival curve and essential statistics such as the median survival time. Kaplan-Meier analysis, which main result is the Kaplan-Meier table, is based on irregular time intervals, contrary to the life table analysis, where the time intervals are regular Figure 2 - Kaplan-Meier Curve. Also, see Real Statistics Support for Kaplan-Meier for a simpler way to produce the survival curve. 3 responses to Survival Curve. Jonathan Davis Ballou. May 25, 2019 at 4:43 pm I just want to check that this is correct What is the KM plotter? The Kaplan Meier plotter is capable to assess the effect of 54k genes (mRNA, miRNA, protein) on survival in 21 cancer types including breast (n=7,830), ovarian (n=2,190), lung (n=3,452), and gastric (n=1,440) cancer.Sources for the databases include GEO, EGA, and TCGA. Primary purpose of the tool is a meta-analysis based discovery and validation of survival biomarkers
The Kaplan-Meier estimator, also known as the product limit estimator, is a non-parametric statistic used to estimate the survival function from lifetime data. In medical research, it is often used to measure the fraction of patients living for a certain amount of time after treatment. In other fields, Kaplan-Meier estimators may be used to measure the length of time people remain. The Kaplan Meier Curve is an estimator used to estimate the survival function. The Kaplan Meier Curve is the visual representation of this function that shows the probability of an event at a respective time interval. The curve should approach the true survival function for the population under investigation, provided the sample size is large. K aplan-Meier curves are widely used in clinical and fundamental research, but there are some important pitfalls to keep in mind when making or interpreting them. In this short post, I'm going to give a basic overview of how data is represented on the Kaplan Meier plot. The Kaplan-Meier estimator is used to estimate the survival function. The visual representation of this function is usually. Survival analysis - Kaplan-Meier Curve Home Categories Tags My Tools About Leave message RSS 2016-05-05 | category Bioinformatics | tag SurvivalAnalysis NCCTG Lung Cancer Data. Description: Survival in patients with advanced lung cancer from the North Central Cancer Treatment Group
Kaplan Meier Survival Analysis using Prism 3. With some experiments, the outcome is a survival time, and you want to compare the survival of two or more groups. Survival curves show, for each plotted time on the X axis, the portion of all individuals surviving as of that time Plotting Survival Curves Using ggplot2 and ggfortify The base R graphics version of the Kaplan-Meier survival curves is not visually appealing. With the help of the ggplot2 and ggfortify packages, nicer plots can be produced. Here is the code and output for the Kaplan-Meier curves with ggplot2 and ggfortify Is it possible to plot a Kaplan-Meier survival curve with confidence limits in SPSS? Resolving The Problem. It is possible to do this as follows: Generate the Kaplan-Meier estimate, and save the estimated survival times and standard errors to the active file,. Kaplan Meier Curve Using Wallmotion Score. As we can see that the difference between the age groups is less in the previous step, it is good to analyse our data using the wallmotion-score group.The Kaplan estimate for age group below 62 is higher for 24 months after the heart condition. After it, the survival rate is similar to the age group.
The Kaplan-Meier Estimator, also called product-limit estimator, provides an estimate of S(t) and h(t) from a sample of failure times which may be progressively right-censored. What you will learn. This tutorial will show you how to: Perform Kaplan-Meier Estimator; How to interpret the results; Steps Running Kaplan-Meier Estimato Github link where you can download the plugin: https://github.com/lukashalim/ExcelSurvivalLearn Data Viz: https://www.udemy.com/course/tableau-specialist-cer..
. We first describe what problem it solves, give a heuristic derivation, then go over its assumptions, go over confidence intervals and hypothesis testing, and then show how to plot a Kaplan Meier curve or curves Kaplan-Meier Method. The Statistics and Machine Learning Toolbox™ function ecdf produces the empirical cumulative hazard, survivor, and cumulative distribution functions by using the Kaplan-Meier nonparametric method. The Kaplan-Meier estimator for the survivor function is also called the product-limit estimator.. The Kaplan-Meier method uses survival data summarized in life tables Important things to consider for Kaplan Meier Estimator Analysis. 1) . We need to perform the Log Rank Test to make any kind of inferences. 2) . Kaplan Meier's results can be easily biased. The Kaplan Meier is a univariate approach to solving the problem 3) . Removal of Censored Data will cause to change in the shape of the curve. This will create biases in model fit-u Edward L. Kaplan and the Kaplan-Meier Survival Curve LUKAS JASTALPERS University of Amsterdam, The Netherlands EDWARD LKAPLAN University of Minnesota Medical School, USA In June 1958, Edward L Kaplan (1920-2006) and Paul Meier (1924-2011) published an innovative statistical method to estimate survival curves when including incomplete.
LIFETEST to compute the Kaplan-Meier curve (1958), which is a nonparametric maximum likelihood estimate of the survivor function. The Kaplan-Meier plot (also called the product-limit survival plot) is a popular tool in medical, pharmaceutical, and life sciences research. The Kaplan-Meier plot contains ste 1 Paper 156-30 A SAS® Macro to Generate Enhanced Kaplan-Meier Plots Heidi Christ-Schmidt and Matt Downs Statistics Collaborative, Inc., Washington DC ABSTRACT Many clinical trials have time-to-event endpoints, and Kaplan-Meier estimates of time free of an event are commonl The Number of Records variable is a helper variable used for, as you might have guessed, counting the observations. For that purpose, newer versions of Tableau create a variable based on the name of the data source. However, you can easily create this variable manually by creating a calculated field and placing 1 in the field's definition. Lastly, we define the Kaplan-Meier curve as Kaplan-Meier curve Br J Surg. 2017 Mar;104(4):442. doi: 10.1002/bjs.10238. Authors J Ranstam 1 , J A Cook 1 Affiliation 1 BJS Statistical Editors. PMID: 28199017 DOI: 10.1002/bjs.10238 No abstract available. MeSH terms Humans Kaplan-Meier.
Kaplan-Meier Survival Curve - creating scatter plot with straight lines and markers that will appear like a stair-step down plot I am looking for step-by-step instructions on how to use Excel to create a Kaplan-Meier Survival Curve by taking my data and creating a scatter plot with straight lines and markers, but I want it to look like stairs going down Calculating Kaplan Meier Survival Curves and Their Confidence Intervals in SQL Server. Written by Peter Rosenmai on 1 Jan 2016. I provide here a SQL Server script to calculate Kaplan Meier survival curves and their confidence intervals (plain, log and log-log) for time-to-event data Kaplan-Meier curves typically have the proportion surviving on the vertical (Y) axis and the age or time in years on the horizontal (X) axis bisec: Bisection algorithm in Beta distribution data2: RPEXE_fitting df: JAMA Breast cancer exact_pvalue: P-value for the two exponential comparison in Han et... gamllik: Log likelihood from the gamma distribution km: Kaplan-Meier curve km_blacksolid: Kaplan-Meier curve km_combine: Comparing two Kaplan Meier curves in one plot km_log: Plot a Kaplan Meier curve in log scal
With increasing follow-up time, the curve is based on fewer and fewer cases, therefore becoming progressively less reliable; hence it is conventional to truncate the survival curve when fewer than five cases remain. The Kaplan-Meier method gives an unbiased estimate of survival only if censored cases are typical of the whole series of interest. Kaplan-Meier analyses are also used in nonmedical disciplines. The purpose of this article is to explain how Kaplan-Meier curves are generated and analyzed. Throughout this article, we will dis-cuss Kaplan-Meier estimates in the context of survival before the event of interest. Two small groups of hypothetical data ar Kaplan-Meier Estimator The Kaplan-Meier estimator is a nonparametric estimator which may be used to estimate the sur-vival distribution function from censored data. The estimator may be obtained as the limiting case of the classical actuarial (life table) estimator, and it seems to have been ﬁrst proposed by B¨ohmer  The Kaplan-Meier procedure is a method of estimating time-to-event models in the presence of censored cases. The Kaplan-Meier model is based on estimating conditional probabilities at each time point when an event occurs and taking the product limit of those probabilities to estimate the survival rate at each point in time
Kaplan-Meier curve: GVHD The result of all these calculations is usually summarized in a plot called a Kaplan-Meier curve: 0 20 40 60 80 0.0 0.2 0.4 0.6 0.8 1.0 Time on study (Days) Probability (GVHD-free) 32 29 18 16 16 32 26 25 25 22 MTX MTX+CSP MTX MTX+CSP Patrick Breheny Survival Data Analysis (BIOS 7210) 19/2 Kaplan-Meier method's . . . main focus is on the entire Sponsorships: This work was supported by National Cancer Institute curve of mortality rather than on the traditional clinical Cancer Center Support Grant P30 CA091842. concern with rates at fixed periodic intervals.3 Looking at the ends of the curves or points within them may easily miss the real message
Watch this brief video describing how to create Kaplan-Meier survival curves in NCSS statistical analysis and graphics software Kaplan-Meier analysis is largely used in nephrology to estimate a population survival curve from a sample. If patients are followed-up until death, the survival curve can be estimated simply by computing the fraction survival at each time point. Kaplan-Meier analysis allows the estimation of surviva Hello all, I am learning how to graph Kaplan-Meier Curve. I used sashelp.bmt as an example to practice. I know how to get the graph with proc lifetest or proc sgplot. But now I want to add stats (Median time, log-rank p-value, 95% CI) on the graph, putting them on the topright. I appreciate.. of the Kaplan-Meier estimator. In this paper we suggest a new smooth version of the Kaplan-Meier estimator using a Bezier curve. Bezier smoothing is a very popular technique in computational graphics, especially for computer-aided-geometric-design. See Farin (2001) for a detailed discussion on Bezier curves
1-e_i/d_i: This is the Kaplan Meier curve calculation that we will need to perform a running product on. So, we now create a measure for the calculation our Kaplan Meier curve. This is the Survival Curve, or specifically the probability of survival at ti - which is 1 - the hazard function (probability of not surviving) . Censored patients contribute information that no event occurred up to the point of censoring, avoiding discarding this useful information Figure 3: Kaplan-Meier Curve of IRC-Assessed Progression-Free Survival (ITT Population) Claim 1a - risk reduction (valid application until April 2021) Product Y demonstrated superior PFS compared with placebo: 81% reduction in risk of progression or death vs. placebo (HR: 0.19 [95% CI: 0.13‑0.28]; p<0.0001) Qualification for claim 1 14.2 Survival Curve Estimation. There are parametric and non-parametric methods to estimate a survivor curve. The usual non-parametric method is the Kaplan-Meier (KM) estimator. The usual parametric method is the Weibull distribution, of which the exponential distribution is a special case. In between the two is the Cox proportional hazards model, the most common way to estimate a survivor curve
The curve will drop to zero when a death happens after the last censoring. Make sure your data table is sorted by X value (which Prism can do using Edit..Sort). Look at the subject in the last row. If the Y value is 1 (death), the curve will descend to 0% survival. If the Y value is 0 (censored), the curve will end above 0% Survival analysis (Kaplan-Meier curves): a method to predict the future Análise de sobrevida (curva de Kaplan-Meier): um método para prever o futuro Rodrigo Pessoa Cavalcanti Lira1 , Rosalia Antunes-Foschini2, Eduardo Melani Rocha2 1. Department of Ophthalmology, Faculty of Medicine, Universidade Federal de Pernambuco, Recife, PE, Brazil. 2 Kaplan-Meier is a statistical method used in the analysis of time to event data. Time to event means the time from entry into a study until a particular event, for example onset of illness. This method is very useful in survival analysis as it is used by the researchers to determine and/or analyze the patients or participants who lost to follow up or dropped out of the study, those who. expected Kaplan-Meier curves is what we would intuitively like to minimize •Disadvantages •No measure of uncertainty (no probabilistic analysis) •Does not weight the minimization of the curve by certainty, e.g. at later time points KM are more uncertain, might want to weight sum of squared difference at later time points less Kaplan-Meier method was used to estimate the recurrence-free survival (RFS) and progression-free survival curves and difference was determined by the log-rank test. Univariate and multivariate analyses were performed to determine the predictive factors through a Cox proportional hazards analysis model
Figure 1: Kaplan-Meier curve for the simple example described in the text. 0 10 20 30 40 50 60 70 80 90 100 0 50 100 150 200 survival probability (%) weeks astrocytoma glioblastoma Figure 2: Kaplan-Meier curves for the example of Bland and Altman . (Color-coded.) The Kaplan-Meier survival probability estimates at 12 months were about 0.59 for intervention and 0.43 for control. Kaplan-Meier survival curves for length of time after randomisation until occurrence of the primary endpoint (death from any cause or hospital readmission for heart failure) for the intervention and control treatment groups For Kaplan-Meier curves, this may be the P-value derived from the log-rank test, whereas for Cox regression, hazard ratios may be presented together with their confidence intervals. Therefore, according to Pocock et al., Figure 3d would be the best way to present the data in example 3 kaplanmeier - Python package to compute the kaplan meier curves, log-rank test, and make the plots. Star it if you like it! Installation. Install kaplanmeier from PyPI (recommended). kaplanmeier is compatible with Python 3.6+ and runs on Linux, MacOS X and Windows. Distributed under the MIT license. Requirements. Create environment
Plot Kaplan-Meier Estimates of Survival Curves for Survival Data. Plots Kaplan-Meier estimates of survival curves for survival data. kmTCGA (x, times = times,. . Posted by Nathan Green December 3, 2019 Posted in R. The survival data taken directly from the Kaplan-Meier plot and the at-risk matrix which include the row numbers at which the data is divided in to intervals Create inverse Kaplan Meier curve with response percents and time. Ask Question Asked 4 years, 5 months ago. Active 4 years, 5 months ago. Viewed 1k times -2. I am trying to create an inverse KM plot of the time it takes for patients to respond to drug therapy. Time response.
There are generally two main features that guide interpretation of Kaplan-Meier survival curves - a graphical plot of the survival of 2 or more different groups such as the MBCT and control groups in Figure 2; and a statistical test which estimates the probability that the curves are different from each other over the period of time being tested; although they are not named in the abstract. Guide: Kaplan Meier survival curves . Kaplan-Meier survival curves are a way of graphically displaying the time until study participants developed a particular event or endpoint, often death, or an event such as recurrence of cancer, myocardial infarction, etc I would like to plot a kaplan meier curve (KM) and cumulative events or cumulative incidence function (CIF) in one plot as a lattice. I have switched recently from SAS to R, and in SAS you can do it all in one step using a macro (See this image), but I couldn't find something similar in R yet.. Currently, I run a code for two separate graphs Kaplan meier survival curves and the log-rank test 1. Seminar in Statistics: Survival AnalysisChapter 2Kaplan-Meier SurvivalCurves and the Log-Rank TestLinda Staub & Alexandros Gekenidis March 7th, 2011 2 Kaplan Meier curves: an introduction - GitHub Page
Survival (Kaplan-Meier) Curves Made Easy Carey Smoak, Roche Molecular Systems, Inc., Pleasanton, CA ABSTRACT With the advent of ODS GRAPHICS for SAS® 9.1, survival (Kaplan-Meier) curves can easily be created. Previously one had to create an ODS output dataset from PROC LIFETEST and then use SAS/Graph® to create a survival curve Figure 5. Kaplan-Meier plot including quartile survival times with confidence limits and unadjusted hazard ratios with confidence limits. Also, intersection points of curves with the quartile reference lines are marked. RECOMMENDED READING SAS/STAT 14.3 User Guide Chapter 23. Customizing the Kaplan-Meier Survival Plot Using the Kaplan-Meier curves from published sources can help you to generate your own time-varying survival curves for use in a Markov model. Using the Hoyle and Henley's Excel template to generate the survival probabilities, which are then used in an R script to generate the lambda and gamma parameters, provides a powerful tool to integrate Weibull parameters into a Markov model 4) Kaplan-Meier curve I would like to be able to plot one Kaplan-Meier curve using a combination of the imputed datasets. But unfortunately, here is where I am stuck. I have only managed to plot graphs per imputation
Lo stimatore di Kaplan-Meier, noto anche come stimatore del prodotto limite, è uno stimatore che si usa per stimare la funzione di sopravvivenza di dati relativi alla durata di vita.. Nella ricerca medica, si usa spesso per misurare la frazione di pazienti che vivono per una certa quantità di tempo dopo il trattamento. In economia, si può usare per misurare la lunghezza del tempo in cui le. A survival curve is a chart that shows the proportion of a population that is still alive after a given age, or at a given time after contracting some type of disease.. This tutorial shows how to create a survival curve in Excel. Creating a Survival Curve in Excel. Suppose we have the following dataset that shows how long a patient was in a medical trial (column A) and whether or not the. Kaplan-Meier 曲線の縦軸は None を渡すとエラーになるので場合分け if ax is None: ax = kmf. plot else: ax = kmf. plot (ax = ax) plt. title ('Kaplan-Meier Curve') plt. show Cox比例ハザードモデル(CoxPH model). This tutorial shows how to prepare for drawing Kaplan-Meier Survival Curve. This tool has often been applied to test survival rates of treated and non-treated groups. But with Subio Platform and stored data sets, you can easily test survival rates of grouped patients by gene expression levels of a specific genes, or by methylation levels of tumor suppressor genes
Kaplan Meier survival curve (KM) We will focus on plotting the KM curve. In order to test the similarities of curves we have to make a log rank test which we will describe later The Kaplan-Meier procedure is not limited to the measurement of survival in the narrow sense of dying or not dying. It can also be used to estimate the time-defined probabilities for the failure of an instrument or device of a certain type; or alternatively, to estimate the time-defined probabilities for some particular type of success (e.g., finding employment after becoming unemployed) Kaplan-Meier using SPSS Statistics Introduction. The Kaplan-Meier method (Kaplan & Meier, 1958), also known as the product-limit method, is a nonparametric method used to estimate the probability of survival past given time points (i.e., it calculates a survival distribution) We have described the basics of Kaplan-Meier survival curves by using two very small comparison groups as examples so that the details of construction and analysis could be easily seen. Despite what appeared to be a great different between the two very small groups, the log rank test showed the two curves were not significantly different (P=0.08)
KAPLAN-MEIER CURVE. length of time from study entry to disease end-point for a treatment and control group; from this curve, we can derive:-> median time (time at which 50% of cases resolve)-> mean time (average resolution time) allows comparisons of patients throughout study and provides information on patients who may be lost to follow u Kaplan-Meier Curve . A curve that starts at 100% of the study population and shows the percentage of the population still surviving (or free of disease or some other outcome) at successive times for as long as information is available The calculation of the Kaplan-Meier survival curve for the 25 patients randomly assigned to receive 7 linoleic acid is described in Table 12.2 . The + sign indicates censored data. Until 6 months after treatment, there are no deaths, 50 S(t) 1. The effect of the censoring is to remove from the alive group those that are censored
The Kaplan-Meier (KM) estimation method. The Kaplan-Meier (KM) method is used to estimate the probability of experiencing the event until time t, S KM (t), from individual patient data obtained from an RCT that is subject to right-censoring (where some patients are lost to follow-up or are event-free at the end of the study period).The method works by summarising the IPD in the form of a. Re: Kaplan-Meier Curve Posted 12-07-2017 02:59 PM (1220 views) | In reply to Sujithpeta Patients without time, i.e. NULL isn't actually censored, they just didn't get a recurrent disease for the study time period The Kaplan-Meier survival curve represents the probability of surviving, or remaining event free, in a given time period while identifying changes in probability at intervals. In generating the Kaplan-Meier curve we utilized the Kaplan-Meier estimate to measure the fraction of mice with continued bleeding for a certain amount of time after treatment
Kaplan-Meier analyses are also used in nonmedical disciplines. The purpose of this article is to explain how Kaplan-Meier curves are generated and analyzed. Throughout this article, we will discuss Kaplan-Meier estimates in the context of survival before the event of interest Kaplan-Meier curves are often presented with 95 per cent confidence intervals and a difference between curves can be tested statistically, most commonly using the log rank test. The curve can be presented upside down (by swapping the event and non-event). Two issues are particularly important when interpreting Kaplan-Meier curves
Kaplan Meier curves of overall survival in all pooled GBM data (n=300) A. Performance Status. B. Presence of neurological deficits. C. Time since initial diagnosis. D. Baseline administration of steroids. E. Number of target lesions. F. Maximum diameter of the largest lesion n = number of patients with available clinical data. Please kindly cite our paper to support further development: Gyorffy B, Lanczky A, Szallasi Z. Implementing an online tool for genome-wide validation of survival-associated biomarkers in ovarian-cancer using microarray data of 1287 patients, Endocrine-Related Cancer. 2012 Apr 10;19(2):197-208 Comparing Two KM Curves As you can see in the two Kaplan Meier curves (below) the risk ratio would be different for different follow-up times. When a Kaplan-Meier analysis is presented in the medical literature, a p-value that summarizes the probability that the two curves differ over their entire lengths is usually given Survival Analysis and Kaplan-Meier Curves Demo Kaylee Ho, MS 2/14/2020. Primary Biliary Cirrhosis (PBC) Dataset. This data is from the Mayo Clinic trial in primary biliary cirrhosis (PBC) of the liver conducted between 1974 and 1984 Kaplan Meier curve with different time lengths across groups. 1. Survival - comparing Kaplan-Meier curve to handful of points. 2. Weighted Kaplan-Meier Curve Log Rank Test. 1. How to word the interpretation of a Kaplan-Meier estimate. 5. Visually Comparing the Kaplan-Meier Curve to the Cox PH Model Curve. 1
Figure 1 Kaplan-Meier cumulative probability curve showing the incidence of radiation-induced scleral necrosis (SNEC). One of the advantages of survival analysis is that it considers both data from participants who develop the event and data from those who are censored and can compare survival medians between different groups when the event occurs in at least 50% of the participants I am trying to plot adjusted Kaplan-Meier curves. I know publications like to see something graphical. But using R, I don't know how to go about adjusting for something like age, gender, income when graphing a survival curve. Otherwise my curves will always be just crude and unadjusted, which I'm guessing people will not like. Any ideas Kaplan-Meier analysis can be used to test the statistical significance of differences between the survival curves associated with two different treatments. In recent years, Drug survival curves for patients subdivided in different ways: (A) two groups of 303 patients defined by recruitment date being before (top curve). The weak convergence of the Kaplan-Meier estimate for censored survival data to a Gaussian process is used to construct asymptotic confidence bands for the survival curves. The method involves transforming to obtain Brownian motion and using straight line boundaries and hitting probabilities for Brownian motion
KaplanMeierFitter¶ class lifelines.fitters.kaplan_meier_fitter.KaplanMeierFitter (alpha: float = 0.05, label: str = None) ¶. Bases: lifelines.fitters.NonParametricUnivariateFitter Class for fitting the Kaplan-Meier estimate for the survival function A Multifaceted Approach to Generating Kaplan-Meier and Waterfall Plots in Oncology Studies, continued 2 Kaplan-Meier curve is that the method can take into account some types of censored data, particularly right-censoring, which occurs if a patient withdraws from a study, i.e. is lost from the sample before the final outcome is observed In the context of competing risks the Kaplan—Meier estimator is often unsuitable for summarizing failure time data. We discuss some alternative descriptive methods including marginal probability and conditional probability estimators I had a request to build a Kaplan-Meier Curve recently and was supplied the following link which explains how the curve can be calculated: - 51794
Kaplan-Meier analysis: ( kap'lăn mī'ĕr ), a method of calculating survival of a patient population in which the increments are the actual survival times of the patients Stata: Data Analysis and Statistical Software PRODUCTS. Stata. Why Stata Features New in Stata 17 Discipline Create survival curves using kaplan-meier, the log-rank test. - erdogant/kaplanmeier Kaplan Meier Curve 15 Jan 2016, 08:33. Hi, I've been struggling with a Kaplan Meier survival curve and can't seem to find a solution anywhere. I have mortality data extending over an 11 year period. I began recording death events 24 months after an initial survey. The. There are several graphical methods for spotting this violation, but the simplest is an examination of the Kaplan-Meier curves. If the curves cross, as shown below, then you have a problem. Likewise, if one curve levels off while the other drops to zero, you have a problem Dear all, I'm using the survival package with R 2.4.0 on Mac OS X 10.4.8. I have two core statistics books (one of which is Altman's medical stats book) which suggest showing the number of individuals at risk at different time intervals on the Kaplan-Meier curve. My plot shows two curves that later cross, because of one significant outlier. I have two queries: Is there an easy way of.