help for qcount

Quantile Regression for Count Data

qcount depvar [varlist] [if exp] [in range] , quantile(number) [ repetition(integer)]

Note: the number in quantile should be in the interval (0,1).

After estimation, marginal effects (at the mean of the explanatory variables) are obtained as:

qcount_mfx [if exp] [in range]


qcount estimates quantile regression models for count data using the jittering method suggested by Machando and Santos Silva (2005).


Quantile(number) specifies the quantile to be estimated. This is a required option.

repetition(integer) specifies the number of jittered samples to be used to calculate the parameters of the model. If no specified, 1000 repetitions is the default.


. qcount y x1 x2, q(0.5) rep(5000) . qcount_mfx


Alfonso Miranda (A.Miranda@econ.keele.ac.uk) Centre for Economic Research, Keele University, Keele, Staffordshire ST5 5BG, UK.

References (available from the author)

Machado, J., Santos Silva, J.M.C. (2005) Quantiles for Counts. Journal of the American Statistical Association 100, 1226--1237.

Miranda, A. Planned Fertility and Family Background: A Quantile Regression for Counts Analysis. Journal of Population Economics (forthcoming).

Also see

Manual: [U] 23 Estimation and post-estimation commands, [U] 29 Overview of Stata estimation commands,

Online: help for qreg.