*Choose Index below for a list of all words and phrases defined in this glossary.*

**Kaplan-Meier **- The Kaplan-Meier method is a nonparametric (actuarial) technique for estimating time-related events (the survivorship function). 1 Ordinarily it is used to analyze death as an outcome. It may be used effectively to analyze time to an endpoint, such as remission.

It is a univariate analysis and is an appropriate starting technique. It estimates the probability of the proportion of individuals in remission at a particular time, starting from the initiation of active date (time zero), is especially applicable when length of follow-up varies from customer to customer, and takes into account those customer lost to follow-up or not yet in remission at end of study (censored customers, assuming the censoring is non-informative). It is therefore the instrument of choice in evaluating remissions following loosing a customer. Since the estimated survival distribution for the cohort study has some degree of uncertainty, 95% confidence intervals may be calculated for each survival probability on the "estimated" curve.

A variety of tests (log-rank, Wilcoxan and Gehen) may be used to compare two or more Kaplan-Meier "curves" under certain well-defined circumstances. Median remission time (the time when 50% of the cohort has reached remission), as well as quantities such as three, five, and ten year probability of remission, can also be generated from the Kaplan-Meier analysis, provided there has been sufficient follow-up of customers.

The Kaplan-Meier technique is usually only useful as a method of preliminary evaluation, since it is purely a descriptive method for the evaluation of one variable.

[Category=Data Quality ]

*Source: iSixSigma, 29 January 2011 10:21:56, http://www.isixsigma.com/index.php?option=com_glossary *

Data Quality Glossary. A free resource from GRC Data Intelligence. For comments, questions or feedback: dqglossary@grcdi.nl