*! version 1.1.9 12feb2024

Title

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

Syntax

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

stai #a1 #a0 #t1 #t0, data(pt) [options]

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

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

detail display additional statistics

pe(#) proportion of exposed in the population; detail option only

nst(string) name of the study (label)

Description

Measures of Association for non stratified person-time data.

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

Proportion of exposed in the population [pe()] may be included when additional statistics [detail] are
computed.

stai is the immediate form of sta; see immed. The sequence of #a1, #a0, #t1
and #t0 come from a contingency table:

|UnExposed| Exposed | Total

+
+
+------

Cases | a0 | a1 | m1

Person-time | t0 | t1 | t

+
+
+------

Examples

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

. sta Bladder Smoking Time, data(pt) detail

. stai 23 25 44607 141634, data(pt) detail

Stored results

The command stores the following in r():

Scalars

r(a0) number of cases unexposed

r(a1) number of cases exposed

r(m1) total number of cases

r(t0) unexposed person-time

r(t1) exposed person-time

r(t) total person-time

r(i0) unexposed incidence rate

r(i1) exposed incidence rate

r(i) total incidence rate

r(id) incidence rate difference

r(lb_id) lower bound of CI for id

r(ub_id) upper bound of CI for id

r(ir) incidence rate ratio

r(lb_ir) lower bound of CI for ir

r(ub_ir) upper bound of CI for ir

r(se_ir) estimate of standard error of ir

r(lb_ir_exact) exact lower bound of CI for ir

r(ub_ir_exact) exact upper bound of CI for ir

r(chi2) chi-squared

r(p) two-sided p-value

r(pe_pop) proportion of exposed in the population (detail only)

r(idp) incidence rate difference in the population (detail only)

r(lb_idp) lower bound of CI for idp (detail only)

r(ub_idp) upper bound of CI for idp (detail only)

r(se_idp) estimate of standard error of idp (detail only)

r(afe) attributable fraction exposed (detail only, whenever it's convenient)

r(lb_afe) lower bound of CI for afe (detail only, whenever it's convenient)

r(ub_afe) upper bound of CI for afe (detail only, whenever it's convenient)

r(afp) attributable fraction population (detail only, whenever it's convenient)

r(lb_afp) lower bound of CI for afp (detail only, whenever it's convenient)

r(ub_afp) upper bound of CI for afp (detail only, whenever it's convenient)

r(se_afp) estimate of standard error of afp (detail only, whenever it's convenient)

r(pfe) preventable fraction exposed (detail only, whenever it's convenient)

r(lb_pfe) lower bound of CI for pfe (detail only, whenever it's convenient)

r(ub_pfe) upper bound of CI for pfe (detail only, whenever it's convenient)

r(pfp) preventable fraction population (detail only, whenever it's convenient)

r(lb_pfp) lower bound of CI for pfp (detail only, whenever it's convenient)

r(ub_pfp) upper bound of CI for pfp (detail only, whenever it's convenient)