{smcl}
{* 19aug2004}{...}
{hline}
help for {hi:dtobit}{right:(STB-56: sg144; SJ4-3: sg144_1)}
{hline}


{title:Marginal effects of the tobit model}

{p 8 16 2}
{cmd:dtobit} 
[{cmd:,} {opt at(matname)}
{opt c:ensor}
{opt b:rief}
{opt nod:iscrete} 
{opt lev:el(#)} ]


{title:Description}

{pstd}
{cmd:dtobit} provides a table of marginal effects evaluated at the means of the
independent variables by default, or at the observed censoring rate of the
dependent variable if ^censor^ is specified, or at user specified points if
{opt at(matname)} is specified.  The marginal effects are computed for the
latent dependent variable, the expected value of the dependent variable
conditional on being uncensored, the unconditional expected value of the
dependent variable, and the probability of being uncensored.  For dummy
variables, by default, {cmd:dtobit} will report the discrete changes unless
the {opt nodiscrete} option is specified.


{title:Options}

{phang}
{opt at(matname)} specifies the points around which the marginal effects are
   to be estimated. The default is to estimate the effects around the means
   of the independent variables.

{phang}
{opt censor} specifies that the marginal effects should be evaluated at the
   observed censoring rate of the dependent variable. This option is not
   allowed with two-tailed censoring case. {opt at(matname)} and {opt censor}
   cannot be specified at the same time.

{phang}
{opt brief} will simplify the output.  Standard deviations of the estimates
   and the confidence intervals will be excluded from the table.

{phang}
{opt nodiscrete} treats dummy variables as continuous ones. If nodiscrete is not
   specified, the marginal effect of a dummy variable is calculated as the
   discrete change in the expected value of the dependent variable as the
   dummy variable changes from 0 to 1.


{title:Example}

	{cmd:. tobit mpg trunk weight, ll(17)}
	{cmd:. dtobit}
	{cmd:. dtobit, brief}
	{cmd:. dtobit, brief censor}
	{cmd:. mat M=(12, 2500, 1)}
	{cmd:. dtobit, at(M)}


{title:Author}

   Ronna Cong
   StataCorp
   rcong@stata.com


{title:Also see}

{psee}
 Manual:  {hi:[U] 26 Estimation and post-estimation commands}{break}
          {hi:[U] 35 Overview of model estimation}

{psee}
Online:  help for {help est}; {help cnreg}, {help intreg},
{help test}, {help testnl}, {help tobit}, {help vce}
{p_end}
