{smcl}
{* *! version 1.1  Nov2007}{...}
{cmd:help dunnett}
{hline}

{title:Title}

{p2colset 9 20 22 2}{...}
{p2col :{hi: dunnett} {hline 2 }}The Dunnett Method for a Comparison 
of All Treatments with a Control{p_end}
{p2colreset}{...}


{title:Syntax}

{p 8 15 2}
{cmdab:dunnett}
{it:response_var}
{it:factor_var}
{ifin}{cmd:,}
{opt con:trol(#)}
[{it:options}]

{synoptset 20 tabbed}{...}
{synopthdr}
{synoptline}
{syntab:Main}
{p2coldent:* {opt con:trol(#)}}set control value of factor_var  {p_end}
{synopt :{opt ci(#)}}set confidence level; the default is {cmd:ci(95)} {p_end}
{synopt :{opt s:ide(#)}}set interval type; the default is {cmd:side(2)} {p_end}
{synopt :{opt no:label}}show numeric codes, not labels {p_end}
{synopt :{opt sep:arator(#)}}draw separator line after every {it:#} groups; default
is {cmd:separator(5)}{p_end}
{synopt :{opt mi:ssing}}treat missing values of {it: factor_var} as a category {p_end}
{synoptline}{...}
{p2colreset}
{p 4 6 2}
  * {opt control(#)} is required.{p_end}

{title:Description}

{pstd}
The {opt dunnett} command compares all treatments to a control by implementing
the Dunnett Method. Simultaneous confidence intervals for differences between
each individual group mean and the control mean are reported using the tables
from Dunnett(1955) and Dunnett(1964).

{pstd}
Because the table values are used, the {opt dunnett} command can only construct 95% and 99%
 simultaneous confidence intervals for and requires that the degree of freedom to be 
at least five. The Dunnett Method also requires that all treatments have the same sample size
for the validity of the test to hold.

{pstd} 
If a two-sided test is specified, the number of groups in {it: factor_var} must be less 
than 21 including the control. If a one-sided test is specified, the number of groups 
must be less than 10 including the control.

{title:Options}

{dlgtab:Main}

{phang}{opt control} specifies the control value of factor_var that {opt dunnett} will use 
as the control to compare all other groups to. This value must be numberic and a value of 
factor_var.

{phang}{opt ci(#)} specifies the confidence level, as a percentage, for simultaneous confidence 
intervals. The default is {opt ci(95)} and can currently only be changed to {opt ci(99)}.

{phang}{opt side(#)} specifies the type of test to be performed. The default is {opt side(2)} where
the two sided simultaneous confidence intervals are reported. When changed to {opt side(1)}, both the 
lower and upper simultaneous bounds are reported for a lower and upper tailed test respectively.

{phang}{opt nolabel} causes the numeric codes to be displayed rather than the value
labels in the reported table. The default is to show the value labels if they exist.

{phang}{opt separator(#)} specifies how often to insert separation lines into the output. 
The default is {opt separator(5)}, meaning that a line is drawn after every five treatments. 
{opt separator(10)} would draw a line after every 10 treatments and {opt separator(0)} suppresses
the separation line.

{phang}{opt missing} requests that missing values of {it factor_var} be 
treated as a category rather than as observations to be omitted from the 
analysis.

{title:Examples}

    Setup
{phang2}{cmd:. webuse rash}{p_end}

{phang}Two-sided simultaneous confidence intervals{p_end}
{phang2}{cmd:. dunnett response clinic, control(1)}{p_end}

{phang}One-sided simultaneous confidence intervals{p_end}
{phang2}{cmd:. dunnett response clinic, control(1) side(1)}{p_end}

{phang}One and two-sided 99% simultaneous confidence intervals{p_end}
{phang2}{cmd:. dunnett response clinic, control(1) ci(99)}{p_end}
{phang2}{cmd:. dunnett response clinic, control(1) side(1) ci(99)}{p_end}

    Setup
{phang2}{cmd:. webuse rash}{p_end}
{phang2}{cmd:. replace clinic = . if clinic==8}{p_end}

{phang}Treat missing values as a category{p_end}
{phang2}{cmd:. dunnett response clinic, control(1) missing}{p_end}


{title:Saved results}

{pstd}
{cmd:dunnett} saves the following in {cmd:r()}:

{synoptset 17 tabbed}{...}
{p2col 5 15 19 2: Scalars}{p_end}
{synopt:{cmd:r(N)}}total number of observations{p_end}
{synopt:{cmd:r(groups)}}number of groups including the control{p_end}
{synopt:{cmd:r(df)}}degrees of freedom{p_end}
{synopt:{cmd:r(mse)}}mean squared error{p_end}
{synopt:{cmd:r(side)}}type of test{p_end}
{synopt:{cmd:r(confidence)}}confidence level of SCI{p_end}
{synopt:{cmd:r(reps)}}number of replications for each group{p_end}
{synopt:{cmd:r(d)}}table value{p_end}
{synopt:{cmd:r(criterion)}}Dunnett criterion{p_end}
{synopt:{cmd:r(control)}}control value{p_end}

{p2col 5 15 19 2: Macros}{p_end}
{synopt:{cmd:r(fact_var)}}factor variable{p_end}
{synopt:{cmd:r(resp_var)}}response variable{p_end}
{p2colreset}{...}

{title:Author}

{p 10 10 2}Theresa Boswell{p_end}
{p 10 10 2}tmb@stata.com{p_end}

{title:Also see}

{psee}
Online:  {manhelp oneway R},
{manhelp anova R},
{manhelp loneway R}
{p_end}


{s6hlp}
{smcl}