Parametric Accelerated Failure Time Models

A Parametric Accelerated Failure Time (AFT) Model analysis invokes the parametric survival models procedure with nonrecurrent life time data. Parametric survival models assume that survival time follow a known distribution, and this analysis fits accelerated failure time models with their model effects proportional with respect to survival time.

Obtaining a Parametric Accelerated Failure Time Models analysis

This feature requires SPSS® Statistics Standard Edition or the Advanced Statistics Option.

  1. From the menus choose:

    Analyze > Survival > Parametric Accelerated Failure Time (AFT) Models

  2. Select a source variable.
Time
Survival
Single numeric variable denoting the duration of the survival time.
Start/End
Numeric variables denoting Start Time and End Time.
Status
Single optional string or numeric variable that determines one of the following status settings:
Failure/Event
Maps a record to a failure/event category. The default value for a string status variable is F.
Right Censoring
Maps a record to a right censoring category. The default value for a string status variable is R.
Left Censoring
Maps a record to a left censoring category. The default value for a string status variable is L.
Interval Censoring
Maps a record to an interval censoring category. For Start/End only. The default value for a string status variable is I.
Unmapped Values Treatment
Controls which category to map the unmapped records to. To delete the records which failed to be mapped, select Exclude them from analysis.
For Survival, the default status for all cases is Failure/Event. For Start/End, the default status is Interval Censoring. Click the Define event button to define an event for the status variable.
Covariate(s)
One or more optional numeric variables to be treated as covariates. Note that a variable cannot be specified by both Covariate(s) and Fixed Factor(s).
Fixed Factor(s)
One or more optional variables to be treated as factors. A variable cannot be specified by both Fixed Factor(s) and Covariate(s).
Left Truncation
Single optional numeric variable for left truncation for Survival only.

This procedure pastes SURVREG AFT command syntax.