A Kaplan-Meier Example

Suppose you want to calculate Kaplan-Meier Estimates for the as given in Figure 8-69. Each row contains the data for one subject. Column A contains the survival time, i.e. the time until death or censure. Column B contains the group number, we are considering two groups of subjects. Column C indicates whether the subject died (0) or was censured (1).

We complete the fields of the Input tab as shown in Figure 8-69. The time column is A2:A21 and the censure column is C2:C21.

Since we have two groups of subjects, on the Groups tab we check the Define multiple groups check box and set up two groups with identifiers 1 and 2 in column B2:B21:

On the Options tab all checkboxes are pre-checked and we leave them that way to obtain a maximum amount of information.

Onthe output tab we choose where we would like the output to be placed. For the purposes of this example we retain the New Sheet target. After clicking OK we get the output shown in Figure 8-71. Note that the graph initially always appears on top of the numerical result and was moved for the screen shot.

B1:F17 shows the results of the first group, G1 to K17 the results of the second group. The graph shows the Kaplan-Meier survival curves for both groups.

M4:N7 shows the result of the Mantel-Haenszel Log-Rank Test. In this case the p-value is larger than 0.3 and we would fail to reject the Null hypothesis. There is no evidence that the survival times differ.