help panell

Title

panell -- Display panel length for a given set of variables

Syntax

panell
[varlist]
[if] [in]
[, options]

Main
suppress suppress display of panel-specific characteristics

generate(newvar) create marker variable newvar

Description

panell displays individual and overall panel length of a given set of variables
of a rectangular longitudinal/panel dataset (also known as time-series cross-section
(TSCS) dataset). The output shows how many observations
are non-missing for one variable or even a certain combination of multiple variables.
This helps the user in getting a detailed overview of the availabilty of
observations for models incorporating a single/multiple exogenous variable(s).
Additionally, the range of the time frame of each panel is displayed and
when panels exhibits gaps (i.e. missing observations that are encased by non-missing
observations within a panel) then those gaps are reported.
Furthermore, overall characteristics of all panels (e.g. the number of panels, range of
time frame, number of panels with observations, etc.) are displayed.

Options

Main

suppress suppresses the output of panel-specific characteristics. You may want to use this
option if the dataset contains a large number of panels.

generate(newvar) creates a dichotomous marker variable
newvar that marks all observations with available information for
all variables in varlist with 1 (otherwise 0, if missing).

Remarks

1. Since panell is exclusively written for use with TSCS
datasets, it is necessary to run the xtset command before executing.

2. The datetime display formats (e.g. yearly,
quarterly, monthly) of the time variable assigned in xtset
are automatically detected and displayed. If the time variable has no datetime display
format assigned, then the integer values of the time variable are shown
in the output.

3. If varlist contains no variables, all variables within the dataset are taken into account (same as
typing panell _all), albeit all string variables will automatically be removed from varlist.

4. If the panel identifying variable has value labels assigned, then these labels automatically
appear in the output.

Examples

Setup

. use "http://www.stata-press.com/data/r12/union.dta", clear

. xtset idcode year

Single variable with univariate statistics

. panell age

Multiple variables, additional generation of a marker variable

. panell age grade not_smsa south union black, gen(markervar)

Entire Dataset without details on individual panels

. panell, su

Author

Jan Helmdag, Department of Political Science, University of Greifswald, Germany