{smcl}
{* 16June2005}{...}
{hline}
help for {hi:eclpci}
{hline}

{title:Exact and Approximate Confidence Limits for Poisson Counts}

{p 4 14 10}{cmd:eclpci} {it:#obs} [{it:#exp}] [{cmd: ,} {cmdab:l:evel(}{it:#}{cmd:)} {cmdab:f:ormat(%}{it:fmt}{cmd:)} {cmdab:n:ormal} 
{cmdab:ncc:orr}  {cmdab:rb} {cmdab:chi2} {cmdab:chi2c} ]{p_end}

{p 4 14 10} where {p_end}

{p 4 14 10}{it:#obs} observed number of events   {p_end}
{p 4 14 10}[{it:#exp}] expected number of events  {p_end}

{title:Description}

{p 4 10 10}{cmd:eclpci} calculates exact and approximate confidence limits for a Poisson count (#obs). 
It provides a Standardized Mortality Ratio (SMR=#obs/#exp) and its confidence limits if the expected number of events (#exp) is specified. 
It is an immediate command.{p_end}
 
{title:Options}

{p 4 8 2}{cmdab:l:evel(}{it:#}{cmd:)} specifies the width of the confidence interval; see help {help level}.{p_end}

{p 4 8 2}{cmdab:f:ormat(%}{it:fmt}{cmd:)} specifies the display format for presenting numbers.
{cmd:format(%4.3f)} is the default; see help {help format}.{p_end}

{p 4 8 2}{cmdab:n:ormal} specifies the normal approximation to calculate confidence limits of the counts (or SMR).{p_end}

{p 4 8 2}{cmdab:n:ccorr} specifies the normal approximation with continuity correction to calculate confidence limits of the counts (or SMR).{p_end}

{p 4 8 2}{cmdab:rb} specifies approximate limits of the counts (or SMR) as described by Rothman and Boyce (1979) or Breslow and Day (1987){p_end}

{p 4 8 2}{cmdab:chi2} specifies a chi-square with simple continuity correction (eq. 2.10 pag.68, Breslow and Day, 1987){p_end}

{p 4 8 2}{cmdab:chi2c} specifies chi-square with a better approximation to the exact Poisson test (eq. 2.12 pag.69, Breslow and Day, 1987){p_end}

{title:Examples}

     {cmd:* some examples are extracted from Table 2 page 356 of Daly L. (1992) }

     {cmd:. eclpci 1 }
     {cmd:. eclpci 10 }
     {cmd:. eclpci 50 }
     {cmd:. eclpci 100 }
     {cmd:. eclpci 1, ncc}
     {cmd:. eclpci 10, ncc}
     {cmd:. eclpci 50, n }
     {cmd:. eclpci 100, ncc}

     {cmd:. eclpci 18 27.07}
     {cmd:. eclpci 18 27.07, f(%5.4f) rb} 

{title:References}

{p 4 8 2}Daly, L., Simple SAS macros for the calculation of exact binomial and Poisson
confidence limits, Comput Biol Med 22:351-361, 1992.{p_end}

{p 4 8 2}Breslow NE, Day NE., Statistical Methods in Cancer Research: Volume II,
The Design and Analysis of Cohort Studies. Lyon: International Agency for
Research on Cancer, 1987, p.69.{p_end}

{p 4 8 2}Rothman KJ., and Boice JD., Epidemiologic Analysis with a Programmable Calculator (NIH Publication 79-1649),
Washington DC, US Government Printing Office, 1979.{p_end}

{p 4 8 2}Guidelines for Using Confidence Intervals for Public Health Assessment{p_end}
{p 8 8 2}{browse "http://www.doh.wa.gov/Data/Guidelines/WordDocs/CI_guidelines.pdf"}{p_end}

{title:Support}

{p 4 12}{browse "http://nicolaorsini.altervista.org"}{p_end}
{p 4 12}{browse "mailto:nicola.orsini@imm.ki.se?subject=info eclpci":nicola.orsini@imm.ki.se}

{title:Also see}

{p 4 13 2} 
Online:  help for {help propcii}, {help propci}, {help smr}, {help smri}, {help smrby} (if installed)