help for ^clfpois^   95 % Confidence Limits for Rates based on "Poisson" outcom
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cflpois Count Denominator [if] [in] [, ^B^y(string) ^N^(string) ^M^ult(real 10 > 0000.0)]

Where Count : name of variable giving outcome Denominator: variable containing time at risk

^Description^ ---------- Cflpois Confidence Limitis for poisson distributed outcome (Stata 6)

Clfpois is relevant for overall and stratified (conditional) tabulation of incidence rates based on two variables count and time at risk.

This module is almost through testing but ^appropriate caution^ should still be applied until a notice has been given to the stata-list

By default observations with missing (.) will be excluded from the calculation > s, but not from the stratified table.

The rate is calculated as: Count/Denominator

Reference: Stata ^cii^ routine is used for the actual calculation

example: ^cflpois inj pyrs , by(hrs_wk)^

hrs_wk N inj pyrs rate l a h 1-13 234 47 54433 86.3 62.9 - 115.7 14-35 136 38 151370 25.1 17.9 - 34.1 36+ 298 178 729396 24.4 21.0 - 28.3

t N inj pyrs rate l a h Total 668 263 935199 28.1 25.0 - 31.9

^Options^ -------- ^B^y Stratify by this (or these) variables. ^N^ Indicate number of persons on which the calculations are based. Default is that each record counts as one person. The number of per > sons is only used to display the observation counts. ^M^ult Multiplier for rates. Default 100.000. That is rates are counts/100 > 000 time units.

----------------------------------------------------------------------------- Files are: cflpois.ado, cflpois.hlp

Latest version accessible for download from http://www.bola.suite.dk

Examples ---------

. ^cflpois count pyrs . ^cflpois count pyrs, by(sex agegrp) N(persons) . ^cflpois count pyrs, mult(1000) . ^cflpois count pyrs, by(sex agegrp kohort)

Applying if in . ^cflpois c1 pyrs if r > 0^ . ^cflpois c1 pyrs in 1/400^, by(v3)

weights not tested ! Author ------- Jens M.Lauritsen, Accident Analysis Group, Odense University Hospital Odense Denmark. jm.lauritsen@@dadlnet.dk Also see --------- On-line: help for @cc@ @ir@ @epitab@