New Package psidtools available on SSC

[Ulrich Kohler]

Thanks to Kit Baum, the package psidtools has become available on the SSC archive. It can be installed with

. ssc install psidtools

The package contains the command psid, which has several sub-commands. The command provides an interface to the "Panel Study of Income Dynamics" (PSID) and also to the American branch of the "Cross National Equivalence File" (CNEF). psid and its subcommands let the user perform the following tasks:

---

psid install creates Stata datasets from the zip-files downloadable at psid.org without any user intervention.
psid use loads items from several waves of the PSID or CNEF into memory
psid add merges items from several waves of the PSID/CNEF to a PSID/CNEF file in memory
psid long makes data long (and keep the labels)
psid vardoc displays "official" Online variable description in a browser window

---

psid use and psid add are new versions of psiduse and psidadd that have been available on SSC for years. These older programs are bundled with the PSID-Tools for compatibility reasons, but they are no longer maintained. Users of these older programs should use psid use or psid add for new projects.

psid and its subcommands are described in detail in the help file of the command. For the sake of simplicity I attach a pdf of this help file to this posting.

[Marcos Almeida]

Hello, Ulrich,

Congratulations for the new package! Also, for the book you authored, Data Analysis Using Stata. Unfortunately, I cannot see the help file you tried to attach.
Best,
Marcos

[Ulrich Kohler]

I attached it, but it didn't appear for whatever reason. As you asked for it, I try it again here. In any case the help file can be also accessed without installing the package from within Stata:

. view http://fmwww.bc.edu/repec/bocode/p/psid.sthlp

[Marcos Almeida]

Now I can see it, by clicking on the link you provided. Thanks!

[Ulrich Kohler]

Thanks to Kit Baum, the package psidtools was updated on SSC. Users of the package are requested to update their installation with

. adoupdate psidtools, update

The update concerns the handling of the American branch of the "Cross National Equivalence File" (CNEF). The new version offers fully automated installation of the American CNEF files and automatic handling of known inconsistencies in the captialization of variable names of the CNEF data sets.

[Parth Aks]

Hello Ulrich,

Thanks for uploading the package. I am following the accompanying instructions, however I receive error when I use "psid use" as described in your example.
Step 1: I used the PSID install to extract stata files from 1968 to 2013.
Step 2: Next I used the sample code to construct health and age variables.
The error states that that "fam1968.dta not found" even though I have specified the folder using the "using ~[path]". See the two errors below
Error1: If I use "using Users/.../Documents/DATA/PSID , clear design(10)" then the error is "file Users/.../Documents/DATA/PSID/fam1984.dta not found"
Error2: If I use "using /Users/.../Documents/DATA/PSID , clear design(10)" then the error is "file /Users/.../Documents/DATA/PSID/.dta not found"

I am not sure if there is something else that needs to be done between Step 1 and Step 2.

Thanks

[Ulrich Kohler]

Dear Parth,

as it stands, -psid use- always creates datasets with persons -- not families -- as the unit of analysis.Therefore the command only works, if you have installed the individual data file as well. This is the case even if you only use variables from the family files. So, please download the ind2013er zip-file, -psid install- it and try again.

I am just working on an update of -psid use- to work with the new data delivery, which was advertised a few days ago. I will make the point clear in the help file of this new version.

Aside from that please note that you must wait for the update before being able to use variables from the survey round of year 2013.

Uli

[Parth Aks]

Dear Ulrich

Thanks for replying to my post and suggesting the fix. I installed the individual file and as you suggested removed the 2013 family file from the merge code.

I think the following highighlights the issue clearly: I used a truncated portion of the code to just merge 3 year files to see where the problem occurs : 1968, 1969, 1970

"psid use || age_h [68]V117 [69]V1008 [70]V1239 using Users/.../Documents/DATA/PSID2"

The program picks up data from 1970 first. This is fine. Then it goes to 1968 and says that fam1968.dta not found.

So I tried different combinations of years: 70..72 and it always first picks up the last specified year (i.e. 72 in this case) and then cycles to the first specified year (i.e 70) and runs into an error.

I will eagerly wait for your updated version of the code and hope that could resolve this issue.

Thanks

[Ulrich Kohler]

Dear Parth,

this is weird, as -psid use- really does not work backwards. I also cannot reproduce the error here:

. psid use || age_h [68]V117 [69]V1008 [70]V1239 using ~/data/PSID

. d

Contains data from ~/data/PSID/ind2013er.dta
  obs:        15,690                          
 vars:             9                          4 Jun 2015 08:32
 size:       235,350                          
--------------------------------------------------------------------------------
              storage   display    value
variable name   type    format     label      variable label
--------------------------------------------------------------------------------
x11101ll        long    %12.0g                Person identification number
x11102_1968     int     %9.0g                 1968 Interview Number
x11102_1969     int     %9.0g                 1969 Interview Number
x11102_1970     int     %9.0g                 1970 Interview Number
xsqnr_1969      byte    %9.0g                 Sequence Number 69
xsqnr_1970      byte    %9.0g                 Sequence Number 70
age_h1968       byte    %9.0g                 Age Of Head
age_h1969       byte    %9.0g                 Age Of Head
age_h1970       byte    %9.0g                 Age Of Head
--------------------------------------------------------------------------------
Sorted by:
     Note: Dataset has changed since last saved.

I also run the Do-File that you provided, and it runs fine after removing two minor booboos:

(1) variable names age_h, edu_h, and slt_h appeard twice in the do-file. Those should be unique.
(2) Missing blanks before/after the */ and /*. There should be allways a blank after the */ , and a blank before /*.

As it stands I have no idea what is going on on your side. Please first double-check that have the most recent version of the psid-tools:

. which psid
./psid.ado
*! version 2.00  Juni 4, 2015 @ 09:00:04

If you work with an older version, please update:

. adoupdate psidtools, update
. discard

and tray again. If you already work with the most recent version, please run the command with the do-file option.

. psid use || age_h [68]V117 [69]V1008 [70]V1239 using ~/data/PSID, do(debbug)

This will create a Do-File of the steps that are done by the program to retrieve data. Depending on where the error takes place the file might be empty, but chances are that a do-file is produced. If you run the do-file we might get a clue for what is going on.

If you get an empty do-file please report back and I will give you further advices.

[Parth Aks]

Dear Ulrich

Thanks so much for looking into my code so extensively. Really appreciate your suggestions.

Ado-file was indeed an older (Feb) version. I updated it and did two other things: (1) executed it on windows computer and (2) on Stata 13. It worked efficiently.
(Initially I was running the code on Mac using Stata 14.)

There is one last error remaining which is - merging the death files. As in the example in help file, I used "deathyr []ER32050" and it gave an error "unable to create 20deathyr".
I am working on tweaking and assessing if there is some other error on my part. If all else fails, I will again seek your help.

Thanks so much. Your posts and the ado-file have been very helpful.

Regards

[Ulrich Kohler]

Dear Parth,

as far as I know, there are "death files" in the PSID delivery, and the variable you mentioned is in fact part of the ind2013.dta file. The program should work for this variable as well (and it does on my side). From the error message it looks as you don't have "||" in front of "deathyr", or a missing blank in between "||" and "deathyr".

[Nils Gudat]

Dear Ulrich,

First of all, let me say thank you for the great work on this package. I am usually not a STATA user, but this packages makes it worth my while to work with STATA at least for panel creation. After some initial hickups, I've gotten psid use so far as to actually start merging together the panel, but there are two issues I am currently facing:

1. I cannot include any family-level variables from the 1997 survey (e.g. ER10010, ER12080, ER12174, etc), as psid use will abort with the error "variable ER1xxxx not found", even though fam1997er.dta has been succesfully created in the same folder as all the other files by psid install

2. If I exclude the 1997 variables, psid use starts building the panel but aborts with a syntax error related to "rename", apparently upon trying to rename the first variable in the data set. Is it possible that there was a breaking change to the syntax of rename in Stata 14, as this is the version I'm using?

Thanks for your help!

[Ulrich Kohler]

Dear Nils,

good to hear that my program made you a Stata user!

Regarding your problem I have tried to replicate the error here (see code-box) below, but I was unsuccessful. Variables were created as expected and wave 1997 did not pose any problems. Without seeing your acutal command I cannot say much about what has created the error. Have you used -psid install- with the option "lower"?

Uli

.         psid use ///
>           || sexhead ///
>           [68]V119 [69]V1010 [70]V1240 [71]V1943 [72]V2543 [73]V3096 ///
>           [74]V3509 [75]V3922 [76]V4437 [77]V5351 [78]V5851 [79]V6463 ///
>           [80]V7068 [81]V7659 [82]V8353 [83]V8962 [84]V10420 [85]V11607 ///
>           [86]V13012 [87]V14115 [88]V15131 [89]V16632 [90]V18050 [91]V19350 //
> /
>           [92]V20652 [93]V22407 [94]ER2008 [95]ER5007 [96]ER7007 [97]ER10010 /
> //
>           [99]ER13011 [01]ER17014 [03]ER21018 [05]ER25018 [07]ER36018 ///
>           [09]ER42018 [11]ER47318 ///
>           || inchead ///
>           [68]V74 [69]V514 [70]V1196 [71]V1897 [72]V2498 [73]V3051 [74]V3463 /
> //
>           [75]V3863 [76]V5031 [77]V5627 [78]V6174 [79]V6767 [80]V7413 ///
>           [81]V8066 [82]V8690 [83]V9376 [84]V11023 [85]V12372 [86]V13624 ///
>           [87]V14671 [88]V16145 [89]V17534 [90]V18878 [91]V20178 [92]V21484 //
> /
>           [93]V23323 [94]ER4140 [95]ER6980 [96]ER9231 [97]ER12080 [99]ER16463
> ///
>           [01]ER20443 [03]ER24116 [05]ER27931 [07]ER40921 [09]ER46829 ///
>           [11]ER52237 ///
>           || whourshead ///
>         [68]V47 [69]V465 [70]V1138 [71]V1839 [72]V2439 [73]V3027 [74]V3423 ///
>           [75]V3823 [76]V4332 [77]V5232 [78]V5731 [79]V6336 [80]V6934 ///
>           [81]V7530 [82]V8228 [83]V8830 [84]V10037 [85]V11146 [86]V12545 ///
>           [87]V13745 [88]V14835 [89]V16335 [90]V17744 [91]V19044 [92]V20344 //
> /
>           [93]V21634 [94]ER4096 [95]ER6936 [96]ER9187 [97]ER12174 [99]ER16471
> ///
>           [01]ER20399 [03]ER24080 [05]ER27886 [07]ER40876 [09]ER46767 ///
>           [11]ER52175 ///
>           using "~/data/PSID", clear

.         d sexhead* inchead* whourshead*

              storage   display    value
variable name   type    format     label      variable label
--------------------------------------------------------------------------------
sexhead1968     byte    %8.0g                 Sex Of Head
sexhead1969     byte    %8.0g                 Sex Of Head
sexhead1970     byte    %8.0g                 Sex Of Head
sexhead1971     byte    %8.0g                 Sex Of Head
sexhead1972     byte    %8.0g                 Sex Of Head
sexhead1973     byte    %8.0g                 Sex Of Head
sexhead1974     byte    %8.0g                 Sex Of Head
sexhead1975     byte    %8.0g                 Sex Of Head
sexhead1976     byte    %8.0g                 Sex Of Head
sexhead1977     byte    %8.0g                 Sex Of Head
sexhead1978     byte    %8.0g                 Sex Of Head
sexhead1979     byte    %8.0g                 Sex Of Head
sexhead1980     byte    %8.0g                 Sex Of Head
sexhead1981     byte    %8.0g                 Sex Of 1981 Head
sexhead1982     byte    %8.0g                 Sex Of 1982 Head
sexhead1983     byte    %8.0g                 Sex Of 1983 Head
sexhead1984     byte    %8.0g                 Sex Of 1984 Head
sexhead1985     byte    %8.0g                 Sex Of 1985 Head
sexhead1986     byte    %8.0g                 Sex Of 1986 Head
sexhead1987     byte    %8.0g                 Sex Of 1987 Head
sexhead1988     byte    %8.0g                 Sex Of 1988 Head
sexhead1989     byte    %8.0g                 Sex Of 1989 Head
sexhead1990     byte    %8.0g                 Sex Of 1990 Head
sexhead1991     byte    %8.0g                 Sex Of 1991 Head
sexhead1992     byte    %8.0g                 Sex Of 1992 Head
sexhead1993     byte    %8.0g                 Sex Of 1993 Head
sexhead1994     byte    %8.0g                 Sex Of Head
sexhead1995     byte    %8.0g                 Sex Of Head
sexhead1996     byte    %8.0g                 Sex Of Head
sexhead1997     byte    %8.0g                 Sex Of Head
sexhead1999     byte    %8.0g                 Sex Of Head
sexhead2001     byte    %8.0g                 Sex Of Head
sexhead2003     byte    %8.0g                 Sex Of Head
sexhead2005     byte    %8.0g                 Sex Of Head
sexhead2007     byte    %8.0g                 Sex Of Head
sexhead2009     byte    %8.0g                 Sex Of Head
sexhead2011     byte    %8.0g                 Sex Of Head
inchead1968     float   %9.0g                 Hds Labor Income
inchead1969     float   %9.0g                 Labor Inc Head
inchead1970     float   %9.0g                 Labor Inc Head
inchead1971     float   %9.0g                 Labor Inc Head
inchead1972     float   %9.0g                 Labor Inc Head
inchead1973     float   %9.0g                 Hds Tot Labor Y
inchead1974     float   %9.0g                 Tot Labor Inc-Hd
inchead1975     float   %9.0g                 Head Labor Y
inchead1976     float   %9.0g                 Head Total Labor Y
inchead1977     float   %9.0g                 Tot 1976 Labor Incm Head
inchead1978     float   %9.0g                 Tot 1977 Head Labor Y
inchead1979     float   %9.0g                 Tot 1978 Head Labor Y
inchead1980     float   %9.0g                 Tot Hd Labor $ Y 79
inchead1981     float   %9.0g                 Tot Hd Labor $ $ Y 80
inchead1982     float   %9.0g                 Tot Hd Labor $ $ Y 81
inchead1983     float   %9.0g                 Total Head Labor Y 82
inchead1984     float   %9.0g                 Total Head Labor Y 83
inchead1985     float   %9.0g                 Total Head Labor Y 84
inchead1986     float   %9.0g                 Total Head Labor Y 85
inchead1987     float   %9.0g                 Total Head Labor Y 86
inchead1988     float   %9.0g                 Total Head Labor Y 87
inchead1989     float   %9.0g                 Total Head Labor Y 88
inchead1990     float   %9.0g                 Total Head Labor Y 89
inchead1991     float   %9.0g                 Total Head Labor Y 90
inchead1992     float   %9.0g                 Total Head Labor Y 91
inchead1993     float   %9.0g                 Hd 1992 Total Labor Income
inchead1994     float   %9.0g                 Labor Income Of Head-1993
inchead1995     float   %9.0g                 Labor Income Of Head-1994
inchead1996     float   %9.0g                 Labor Income Of Head-1995
inchead1997     float   %9.0g                 Labor Income-Head
inchead1999     float   %9.0g                 Labor Income-Head
inchead2001     float   %9.0g                 Labor Income Of Head-2000
inchead2003     float   %9.0g                 Labor Income Of Head Last Year
inchead2005     float   %9.0g                 Labor Income Of Head-2004
inchead2007     float   %9.0g                 Labor Income Of Head-2006
inchead2009     float   %9.0g                 Labor Income Of Head-2008
inchead2011     float   %9.0g                 Labor Income Of Head-2010
whourshead1968  int     %9.0g                 Yrly Heads Hrs
whourshead1969  int     %9.0g                 Hrs Head Worked
whourshead1970  int     %9.0g                 Hrs Head Worked
whourshead1971  int     %9.0g                 Hrs Head Worked
whourshead1972  int     %9.0g                 Hrs Head Worked
whourshead1973  int     %9.0g                 Hds Ann Work Hrs
whourshead1974  int     %9.0g                 Ann Wrk Hrs-Hd
whourshead1975  int     %9.0g                 Hrs Hd Worked
whourshead1976  int     %9.0g                 Ann Work Hours
whourshead1977  int     %9.0g                 Hd Ann Wrk Hrs In 76
whourshead1978  int     %9.0g                 Hd Ann Wrk Hrs In 77
whourshead1979  int     %9.0g                 Hd Ann Wrk Hrs In 78
whourshead1980  int     %9.0g                 Hd Ann Wrk Hrs In 79
whourshead1981  int     %9.0g                 Hd Ann Wrk Hrs In 1980
whourshead1982  int     %9.0g                 Hd Ann Wrk Hrs In 1981
whourshead1983  int     %9.0g                 Hd Ann Wrk Hrs In 1982
whourshead1984  int     %9.0g                 Hd Ann Wrk Hrs-1983
whourshead1985  int     %9.0g                 Hd Ann Wrk Hrs In 84
whourshead1986  int     %9.0g                 Hd Ann Wrk Hrs In 85
whourshead1987  int     %9.0g                 Hd Ann Wrk Hrs In 86
whourshead1988  int     %9.0g                 Hd Ann Wrk Hrs In 87
whourshead1989  int     %9.0g                 Hd Ann Wrk Hrs In 88
whourshead1990  int     %9.0g                 Hd Ann Wrk Hrs In 89
whourshead1991  int     %9.0g                 Hd Ann Wrk Hrs In 90
whourshead1992  int     %9.0g                 Hd Ann Wrk Hrs In 91
whourshead1993  int     %9.0g                 Hd 1992 Total Work Hours
whourshead1994  int     %9.0g                 Head Total Hours Of Work-1993
whourshead1995  int     %9.0g                 Head Total Hours Of Work-1994
whourshead1996  int     %9.0g                 Head Total Hours Of Work-1995
whourshead1997  int     %9.0g                 Head Total Hours Of Work-1996
whourshead1999  int     %9.0g                 Head Total Hours Of Work-1998
whourshead2001  int     %9.0g                 Head Total Hours Of Work-2000
whourshead2003  int     %9.0g                 Head Total Hours Of Work Last Year
whourshead2005  int     %9.0g                 Head Total Hours Of Work-2004
whourshead2007  int     %9.0g                 Head Total Hours Of Work-2006
whourshead2009  int     %9.0g                 Head Total Hours Of Work-2008
whourshead2011  int     %9.0g                 Head Total Hours Of Work-2010

[Nils Gudat]

Hm, this gets even more confusing. I had not used the "lower" option, so I went and re-did that step with the added -lower. Running my code then gave me another error, this time "variable ER13002 not found" (which is arguably worse, as I can't exclude ER13002 from the analysis as it's the family interview number which is included by default!).
Running your code instead gave me an error "variable V3 not found".

For the sake of completeness, here's what I did:

. psid install using c:/psidtools, lower
ind2013er.dta installed
fam1968.dta installed
fam1969.dta installed
fam1970.dta installed
fam1971.dta installed
fam1972.dta installed
fam1973.dta installed
fam1974.dta installed
fam1975.dta installed
fam1976.dta installed
fam1977.dta installed
fam1978.dta installed
fam1979.dta installed
fam1980.dta installed
fam1981.dta installed
fam1982.dta installed
fam1983.dta installed
fam1984.dta installed
fam1985.dta installed
fam1986.dta installed
fam1987.dta installed
fam1988.dta installed
fam1989.dta installed
fam1990.dta installed
fam1991.dta installed
fam1992.dta installed
fam1993.dta installed
fam1994er.dta installed
fam1995er.dta installed
fam1996er.dta installed
fam1997er.dta installed
fam1999er.dta installed
fam2001er.dta installed
fam2003er.dta installed
fam2005er.dta installed
fam2007er.dta installed
fam2009er.dta installed
fam2011er.dta installed
fam2013er.dta installed
PSID directory is C:\Novell\ZCM\Stata\Stata14-20150610

Followed by:

#delimit ;

psid use
    || relhd
    [68] ER30003  [69] ER30022  [70] ER30045  [71] ER30069  [72] ER30093  
    [73] ER30119  [74] ER30140  [75] ER30162  [76] ER30190  [77] ER30219  
    [78] ER30248  [79] ER30285  [80] ER30315  [81] ER30345  [82] ER30375  
    [83] ER30401  [84] ER30431  [85] ER30465  [86] ER30500  [87] ER30537  
    [88] ER30572  [89] ER30608  [90] ER30644  [91] ER30691  [92] ER30735  
    [93] ER30808  [94] ER33103  [95] ER33203  [96] ER33303  [97] ER33403  
    [99] ER33503  [01] ER33603  [03] ER33703  [05] ER33803  [07] ER33903  
    [09] ER34003  [11] ER34103
    || 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  [07] ER33904
    [09] ER34004  [11] ER34104
    || agehd
    [68] V117  [69] V1008  [70] V1239  [71] V1942  [72] V2542  
    [73] V3095  [74] V3508  [75] V3921  [76] V4436  [77] V5350  
    [78] V5850  [79] V6462  [80] V7067  [81] V7658  [82] V8352  
    [83] V8961  [84] V10419  [85] V11606  [86] V13011  [87] V14114  
    [88] V15130  [89] V16631  [90] V18049 [91] V19349 [92] V20651
    [93] V22406 [94] ER2007 [95] ER5006 [96] ER7006 [97] ER10009
    [99] ER13010 [01] ER17013 [03] ER21017 [05] ER25017 [07] ER36017
    [09] ER42017 [11] ER47317
    || sexhd
    [68] V119  [69] V1010  [70] V1240  [71] V1943  [72] V2543  
    [73] V3096  [74] V3509  [75] V3922  [76] V4437  [77] V5351  
    [78] V5851  [79] V6463  [80] V7068  [81] V7659  [82] V8353  
    [83] V8962  [84] V10420  [85] V11607  [86] V13012  [87] V14115  
    [88] V15131  [89] V16632  [90] V18050  [91] V19350  [92] V20652  
    [93] V22407  [94] ER2008  [95] ER5007  [96] ER7007  /*[97] ER10010  */
    [99] ER13011  [01] ER17014  [03] ER21018  [05] ER25018  [07] ER36018  
    [09] ER42018  [11] ER47318
    || hdhours
    [68] V47  [69] V465  [70] V1138  [71] V1839  [72] V2439  
    [73] V3027  [74] V3423  [75] V3823  [76] V4332  [77] V5232  
    [78] V5731  [79] V6336  [80] V6934  [81] V7530  [82] V8228  
    [83] V8830  [84] V10037  [85] V11146  [86] V12545  [87] V13745  
    [88] V14835  [89] V16335  [90] V17744  [91] V19044  [92] V20344  
    [93] V21634  [94] ER4096  [95] ER6936  [96] ER9187  /*[97] ER12174  */
    [99] ER16471  [01] ER20399  [03] ER24080  [05] ER27886  [07] ER40876  
    [09] ER46767  [11] ER52175
    || hdlbinc
    [68] V74  [69] V514  [70] V1196  [71] V1897  [72] V2498  
    [73] V3051  [74] V3463  [75] V3863  [76] V5031  [77] V5627  
    [78] V6174  [79] V6767  [80] V7413  [81] V8066  [82] V8690  
    [83] V9376  [84] V11023  [85] V12372  [86] V13624  [87] V14671  
    [88] V16145  [89] V17534  [90] V18878  [91] V20178  [92] V21484  
    [93] V23323  [94] ER4140  [95] ER6980  [96] ER9231  /*[97] ER12080  */
    [99] ER16463  [01] ER20443  [03] ER24116  [05] ER27931  [07] ER40921  
    [09] ER46829  [11] ER52237
    || hdedu
    [68] V313  [69] V794  [70] V1485  [71] V2197  [72] V2823  
    [73] V3241  [74] V3663  [75] V4198  [76] V5074  [77] V5647  
    [78] V6194  [79] V6787  [80] V7433  [81] V8085  [82] V8709  
    [83] V9395  [84] V11042  [85] V12400  [86] V13640  [87] V14687  
    [88] V16161  [89] V17545  [90] V18898
    

using C:/Novell/ZCM/Stata/Stata14-20150610;

[Ulrich Kohler]

Uuuh, yes. When I wrote "Have you used the -lower- option?" I meant this as a question, not as an recommendation to use it. Actually, you should not use it if you want to use the other programs of the psidtools.

I was wondering whether there is a blank between the brackets and the variable names in your -psid use- command. There is neither a blank in my command, nor in the output of the PSID data center. If there is a blank, this might create an error (although It will not explain the error connected with the wave of 1997.)