.- help for ^stselpre^ [ec] Feb 10, 20 > 10 .-Fits proportional hazards model to case-cohort data ---------------------------------------------------

^stselpre^ varlist [^if^ exp] [^in^ range] [^, nohr^ ^l^evel^(^#^)^ ^self^ {^bre^slow | ^efr^on | ^exactm^ | ^exactp^} ^nosh^ow ^force^ ]

^stselpre^ is for use with survival-time data; see help @st@. Before using the > command, data must be prepared for case-cohort analysis by ^stcascoh^; see help @stcasco > h@.

Description -----------

^stselpre^ returns estimates and standard errors from proportional hazards fit > to case-cohort data. Coefficients are estimated according to two methods:

- Self-Prentice scheme. Risk sets uses just the sub-cohort member at risk, - Prentice scheme. Risk sets are augmented by non sub-cohort cases when they fa > il.

The asymptotic Self-Prentice method variance-covariance matrix and standard err > ors are computed using the simplification described in Therneau and Li (1999).

The syntax of @predict@ following ^stselpre^ is as in ^stcox^

Options -------

^nohr^ specifies that coefficients rather than hazard ratios are to be displaye > d ^nohr^ may be typed at estimation or when replaying previously estimated re > sults.

^level(^#^)^ specifies the confidence level for the confidence intervals of the coefficients; see help @level@. ^level^ may be also specified when replayin > g previously estimated results.

^self^ specifies that Self-Prentice method coefficient vector is to be saved in > e(b). Prentice method coefficients are saved by default.

^breslow^, ^efron^, ^exactm^, and ^exactp^ each specify a method for handling t > ied deaths that the underlying ^stcox^ command executes. ^efron^ is the default > .

^noshow^ prevents ^stselpre^ from displaying the identities of the key st varia > bles above its output.

^force^ prevents ^stselpre^ from doing some check on the data set previously pr > epared by ^stcascoh^.

Examples --------

. ^stselpre stage age^ . ^xi: stselpre i.stage*i.histol, nohr self^

Also see --------

Manual: ^[R] stcox [R] sttocc^ On-line: help for @stcascoh@ @stcox@ @sttocc@

Reference ---------

Therneau M T, Li H: Computing the Cox Model for Case Cohort Designs. Lifetime Data Analysis 1999; 5: 99-112.

Author ------

Enzo Coviello Epidemiology Unit ASL BT Italy enzo.coviello@@alice.it