*! version 1.1.9 12feb2024

Title

sta -- Association Measures (stratified person-time data)

Syntax

sta var_response var_exposure var_time [if] [in], data(pt)
by(stratify_var) [options]

stai #a11 #a01 #t11 #t01 \ [...] \ #a1i #a0i #t1i #t0i \ [...] \
#a1k #a0k #t1k #t0k, data(pt) [options]

(where k is the number of strata)

method(weight) method of weighting: default is method(mh)

mh Mantel-Haenszel

iv Inverse of Variance

is Internal Standardization

es External Standardization

notables do not show 2x2 tables; by default, 2x2 are shown

level(#) confidence level (%); the default is level(95)

detail display additional statistics

nst(string) name of the study (label)

Description

Measures of Association for stratified person-time data.

The command needs the response, exposure, time and stratify variables to compute the results.

stai is the immediate form of sta; see immed. The sequence of #a1i, #a0i, #t1i
and #t0i come from a contingency table, given k strata:

|Str 1| .. |Str i| .. |Str k

+-----+----+-----+----+-----

Exposed Cases | a11 | .. | a1i | .. | a1k

Person-time | t11 | .. | t1i | .. | t1k

+-----+----+-----+----+-----

UnExposed Cases | a01 | .. | a0i | .. | a0k

Person-time | t01 | .. | t0i | .. | t0k

+-----+----+-----+----+-----

Examples

. use http://metodo.uab.cat/stata/LungFruitSmoking.dta

. sta Lung Fruit Time, data(pt) by(Smoking) method(mh)

. stai 2 18 5144 124474 \ 6 26 3984 28539, data(pt) method(mh)

Stored results

The command stores the following in r():

Matrices

r(Data) 2x2 table data

r(Ratios) ratios (incidence) for each stratum and for the overall

r(Estim) estimations (incidence) for the different methods

r(Chi2) chi2 results