help psid help psiduse, help psidadd

Disclaimer

This program is superseded by psid. It is no longer
maintained and only delivered to allow replication of older
projects. Please use psid If you start a new project. The new program
provides all facilities of psiduse and offers more.

Title

Makes retrievals from PSID real easy

Syntax

psiduse
|| new_stub varname identifers
[
|| new_stub varname identifers
]
using dirname
[
,
use_options
]

psidadd
|| new_stub varname identifers
[
|| new_stub varname identifers
]
[
,
add_options
]

dirname is the name of the directory in which the PSID
files are stored. The term varname identifier refers to PSID
variables. You cannot specify the PSID variable names in terms of a
varlist but have to use the syntax specified below. Finally
new_stub is the prefix of new names for variables that belong
together.

use_options
design(designtype) Design; default: design(balanced)

cnef(numlist) Waves to be used for CNEF data

clear Replace data in memory

correct Correct inconsistent 2005/2007 data delivery

add_options
cneffrom(path) Path to CNEF data

psidfrom(path) Path to PSID data

correct Correct inconsistent 2005/2007 data delivery

Description

psiduse and psidadd perform data retrievals from the
Panel Study of Income Dynamics (PSID) and for the American part of the
Cross National Equivalence File (CNEF). The programs are companions
of soepuse and soepadd which provide a similar
functionality for the German Socio Economic Panel.

The programs create PSID data sets holding the variables
identified by the variable identifiers with names prefixed by
new_stub. psiduse generates a new file and
psidadd merges further variables to a file generated with
psiduse. By default, the created files will have a balanced
panel design, but various other designs could be specified.

To load data from the PSID, psiduse and psidadd
require that the variables are specified very similar to the variable listing
produced by the PSID Data Center.
Here is an example: To create a longitudinal file with
individual ages and subjective health evaluations of the household head
of waves 1991 and 1992 you would specify

. psiduse || age [91]ER30692 [92]ER30736 || shealth [91]V20021 [92]V21321 using ~/data/psid05

or in a format that highlights better the requested format of
the variable identifiers:

. psiduse

|| age [91]ER30692 [92]ER30736

|| shealth [91]V20021 [92]V21321

using ~/data/psid05

This command will produce a longitudinal data set in a balanced
panel design with variable names "age1991" and "age1992" for the age
variables, and "shealth1991" and "shealth1992" for the health
evaluations. The new data set will also contain person and housholds
identifiers using the name conventions of the Cross National Equivalence File.

psiduse and psidadd are constructed for using them
in connection with the
PSID Data Center. Consider
you have been using the PSID Data Center to search the PSID data base
for items concerning health. After founding an item that suits your needs
you have clicked on that item which brought up an item correspondence
list that looks like this

[84]V10877 [85]V11991 [86]V13417 [87]V14513 [88]V15993
[89]V17390 [90]V18721 [91]V20021 [92]V21321 [93]V23180
[94]ER3853 [95]ER6723 [96]ER8969 [97]ER11723 [99]ER15447
[01]ER19612 [03]ER23009 [05]ER26990

This list almost completely resembles the format of the variable
identifiers to be used in psiduse. It can be therefore copied
into the command. Once you did this, you only need to add a name for
the item. This name will be used as a prefix for all variable names
created for that item in the new data set.

The entire psiduse command to load all variables of
the example above will then become

. psiduse

|| health [84]V10877 [85]V11991 [86]V13417 [87]V14513 [88]V15993

[89]V17390 [90]V18721 [91]V20021 [92]V21321 [93]V23180

[94]ER3853 [95]ER6723 [96]ER8969 [97]ER11723 [99]ER15447

[01]ER19612 [03]ER23009 [05]ER26990

using ~/data/psid05

To load data from the CNEF, psiduse and psidadd
require that the prefixes of variable names are listed as variable
identifier, and that the option cnef() is specified. To load,
for example, the pre- and post government incomes of waves 1980 to
1990 one would use

. psiduse || pre i11102 || post i11104 using ~/data/cnef, cnef(1980/1990)

Note that you cannot load CNEF variables and PSID variables with
the same command. Either you use psiduse to load the CNEF
variables and use psidadd to add variables from the PSID, or you
do it the other way around.

Note also that you must not add variables from waves that are
not already included in the file created by psiduse. If you use
psidadd for adding CNEF data to an existing PSID data file, all
waves that are included in the existing file are retained
automatically.

Finnaly note that you must add a set of empty brackets in front
of items that appear only once in the database (i.e. constants).

Options

design(designtype) specifies the design of the panel data
to be created. design(balanced) is used to create a balanced
panel design, i.e. the data will contain only observations interviewed
in all requested waves. design(any) will keep all available
observations in the data set. design(#) with # being an integer
positive number creates data sets with households interviewed # times
or more.

clear specifies that it is okay to replace the data in
memory, even though the current data have not been saved to disk.

cnef(numlist) must be used to load data from the American part of the
Cross National Equivalence File (CNEF).
Specify the waves for which data should be retained inside the parentheses.
The CNEF uses a standardized scheme for variable names which allows
a simplified syntax for the specification of variable identifiers. The
CNEF option lets you access this simplified syntax.

cneffrom(path) By default psidadd assumes that the
data is stored in the directory specified by psiduse. If you
want to add CNEF variables to a PSID data set you must specify the path
to the CNEF data. You have to specify cneffrom() even if the
CNEF data is stored in the PSID directory.

psidfrom(path) By default psidadd assumes that the
data is stored in the directory specified by psiduse. If you
want to add PSID variables to a CNEF data set you must specify the
path to the PSID data. You have to specify psidfrom() even if the
PSID data is stored in the CNEF directory.

correct An early version of the CNEF delivery for 2007
introduced upper cased "LL" in the variable names of three variables
in the files for years 2005 and 2007. Moreover, the data file of 2005
contained 9 dublicate observations. Option correct changes "LL" to
"ll" and removes the dublicates. I hope that this option becomes
superfluos with updated data deliveries.

Example(s)

Constructing Longitudinal Family Records (PSID)

. psiduse || health [84]V10877 [85]V11991 [86]V13417 using .

Constructing Longitudinal Records (CNEF 1984-2005)

. psiduse || pregov i11101 || postgov i11102 using . , cnef(1980(1)1995 1997(2)2005)

Linking Family and Individual Data (PSID)

. psiduse || health [84]V10877 || age [84]ER30432 using .

A more practical example for a longitudinal data set with several items (PSID and CNEF)

. psiduse

|| shealth [84]V10877 [85]V11991 [86]V13417 [87]V14513

[88]V15993 [89]V17390 [90]V18721 [91]V20021 [92]V21321

[93]V23180 [94]ER3853 [95]ER6723 [96]ER8969 [97]ER11723

[99]ER15447 [01]ER19612 [03]ER23009 [05]ER26990

|| age [68]ER30004 [69]ER30023 [70]ER30046 [71]ER30070

[72]ER30094 [73]ER30120 [74]ER30141 [75]ER30163 [76]ER30191

[77]ER30220 [78]ER30249 [79]ER30286 [80]ER30316 [81]ER30346

[82]ER30376 [83]ER30402 [84]ER30432 [85]ER30466 [86]ER30501

[87]ER30538 [88]ER30573 [89]ER30609 [90]ER30645 [91]ER30692

[92]ER30736 [93]ER30809 [94]ER33104 [95]ER33204 [96]ER33304

[97]ER33404 [99]ER33504 [01]ER33604 [03]ER33704 [05]ER33804

|| disable [72]V2718 [73]V3244 [74]V3666 [75]V4145 [76]V4625

[77]V5560 [78]V6102 [79]V6710 [80]V7343 [81]V7974 [82]V8616

[83]V9290 [84]V10879 [85]V11993 [86]V13427 [87]V14515

[88]V15994 [89]V17391 [90]V18722 [91]V20022 [92]V21322

[93]V23181 [94]ER3854 [95]ER6724 [96]ER8970 [97]ER11724

[99]ER15449 [01]ER19614 [03]ER23014 [05]ER26995

using . , clear design(10)

. psidadd || pregov i11101 || postgov i11102, cnef(~/data/cnef)

Note

psiduse and psidadd are two little unambitious
helper programs. A far more advanced Stata program for working with
large panel data sets is PanelWhiz
by John Haisken DeNew.

Author

Ulrich Kohler, WZB, kohler@wzb.eu

Also see

Online: soepuse (if installed), rgroup (if
installed)