Descriptive statistics for panel data - easy way to get medians?

[Rachel Sleeps]

Hi,

I am using Stata 13 to analyze a large panel. After setting the panel structure In oder to get a feel for the data I used xtsum to get some intial descriptives. I have two groups, which I compare so I ran xtsum for the entire data set, and for each group indivdiually. I realized that there are a few variables that have very high averages and maximum values. I wonder if I am falling for the sensitivity an average value is victim to. Thus, I'd also lilke to report medians. Is there a nice way to get the same output xtsum gives us, but to extend it with median values (at least for the overalls)?

Thanks in advance
/R

[Nick Cox]

Consider tabstat among various alternatives, e.g.

. webuse nlswork
(National Longitudinal Survey.  Young Women 14-26 years of age in 1968)

. xtsum

Variable         |      Mean   Std. Dev.       Min        Max |    Observations
-----------------+--------------------------------------------+----------------
idcode   overall |  2601.284   1487.359          1       5159 |     N =   28534
         between |              1487.57          1       5159 |     n =    4711
         within  |                    0   2601.284   2601.284 | T-bar = 6.05689
                 |                                            |
year     overall |  77.95865   6.383879         68         88 |     N =   28534
         between |             5.156521         68         88 |     n =    4711
         within  |             5.138271   63.79198   92.70865 | T-bar = 6.05689
                 |                                            |
birth_yr overall |  48.08509   3.012837         41         54 |     N =   28534
         between |             3.051795         41         54 |     n =    4711
         within  |                    0   48.08509   48.08509 | T-bar = 6.05689
                 |                                            |
age      overall |  29.04511   6.700584         14         46 |     N =   28510
         between |             5.485756         14         45 |     n =    4710
         within  |              5.16945   14.79511   43.79511 | T-bar = 6.05308
                 |                                            |
race     overall |  1.303392   .4822773          1          3 |     N =   28534
         between |             .4862111          1          3 |     n =    4711
         within  |                    0   1.303392   1.303392 | T-bar = 6.05689
                 |                                            |
msp      overall |  .6029175   .4893019          0          1 |     N =   28518
         between |             .3982385          0          1 |     n =    4711
         within  |             .3238927  -.3304159   1.536251 | T-bar = 6.05349
                 |                                            |
nev_mar  overall |  .2296795   .4206341          0          1 |     N =   28518
         between |             .3684416          0          1 |     n =    4711
         within  |             .2456558  -.7036538   1.163013 | T-bar = 6.05349
                 |                                            |
grade    overall |  12.53259   2.323905          0         18 |     N =   28532
         between |             2.566536          0         18 |     n =    4709
         within  |                    0   12.53259   12.53259 | T-bar = 6.05904
                 |                                            |
collgrad overall |  .1680451   .3739129          0          1 |     N =   28534
         between |             .4045558          0          1 |     n =    4711
         within  |                    0   .1680451   .1680451 | T-bar = 6.05689
                 |                                            |
not_smsa overall |  .2824441   .4501961          0          1 |     N =   28526
         between |             .4111053          0          1 |     n =    4711
         within  |             .1834446  -.6461273   1.215777 | T-bar = 6.05519
                 |                                            |
c_city   overall |   .357218   .4791882          0          1 |     N =   28526
         between |             .4271586          0          1 |     n =    4711
         within  |             .2490022  -.5761154   1.290551 | T-bar = 6.05519
                 |                                            |
south    overall |  .4095562   .4917605          0          1 |     N =   28526
         between |             .4667982          0          1 |     n =    4711
         within  |             .1597932  -.5237771    1.34289 | T-bar = 6.05519
                 |                                            |
ind_code overall |  7.692973   2.994025          1         12 |     N =   28193
         between |             2.542844          1         12 |     n =    4695
         within  |             1.708429  -1.507027   17.12154 | T-bar =  6.0049
                 |                                            |
occ_code overall |  4.777672   3.065435          1         13 |     N =   28413
         between |              2.86512          1         13 |     n =    4699
         within  |             1.650248  -5.522328   15.44434 | T-bar = 6.04661
                 |                                            |
union    overall |  .2344319   .4236542          0          1 |     N =   19238
         between |             .3341803          0          1 |     n =    4150
         within  |             .2668622  -.6822348   1.151099 | T-bar = 4.63566
                 |                                            |
wks_ue   overall |  2.548095   7.294463          0         76 |     N =   22830
         between |             5.181437          0         76 |     n =    4645
         within  |                6.054  -33.95191   64.38143 | T-bar = 4.91496
                 |                                            |
ttl_exp  overall |  6.215316   4.652117          0   28.88461 |     N =   28534
         between |             3.724221          0    24.7062 |     n =    4711
         within  |             3.484133  -9.642671   20.38091 | T-bar = 6.05689
                 |                                            |
tenure   overall |  3.123836   3.751409          0   25.91667 |     N =   28101
         between |             2.796519          0   21.16667 |     n =    4699
         within  |             2.659784  -14.27894   15.62384 | T-bar = 5.98021
                 |                                            |
hours    overall |  36.55956   9.869623          1        168 |     N =   28467
         between |             7.846585          1       83.5 |     n =    4710
         within  |             7.520712  -2.154726   130.0596 | T-bar = 6.04395
                 |                                            |
wks_work overall |  53.98933   29.03232          0        104 |     N =   27831
         between |             20.64508          0        104 |     n =    4686
         within  |             23.96999  -18.43924    131.156 | T-bar = 5.93918
                 |                                            |
ln_wage  overall |  1.674907   .4780935          0   5.263916 |     N =   28534
         between |              .424569          0   3.912023 |     n =    4711
         within  |               .29266  -.4077221    4.78367 | T-bar = 6.05689

.      tabstat *, s(n min p25 p50 p75 max) c(s)

    variable |         N       min       p25       p50       p75       max
-------------+------------------------------------------------------------
      idcode |     28534         1      1327      2606      3881      5159
        year |     28534        68        72        78        83        88
    birth_yr |     28534        41        46        48        51        54
         age |     28510        14        23        28        34        46
        race |     28534         1         1         1         2         3
         msp |     28518         0         0         1         1         1
     nev_mar |     28518         0         0         0         0         1
       grade |     28532         0        12        12        14        18
    collgrad |     28534         0         0         0         0         1
    not_smsa |     28526         0         0         0         1         1
      c_city |     28526         0         0         0         1         1
       south |     28526         0         0         0         1         1
    ind_code |     28193         1         5         7        11        12
    occ_code |     28413         1         3         3         6        13
       union |     19238         0         0         0         0         1
      wks_ue |     22830         0         0         0         0        76
     ttl_exp |     28534         0  2.461539  5.057693  9.128204  28.88461
      tenure |     28101         0        .5  1.666667  4.166667  25.91667
       hours |     28467         1        35        40        40       168
    wks_work |     27831         0        36        52        72       104
     ln_wage |     28534         0  1.361496  1.640541  1.964083  5.263916
--------------------------------------------------------------------------

[Rachel Sleeps]

Wow, cool! Thank you very much!

[Bene Eil]

Is it also possible to show the numbers of unique values of a variable if you use tabstat?

According to help tabstat: stat(n) count all nonmissing value and not only the unique values...

[Nick Cox]

No; tabstat does not support reporting of numbers of distinct values, or at least not without pre-processing.

For a review of that question, including comments on terms "unique", "distinct", etc. see http://www.stata-journal.com/sjpdf.h...iclenum=dm0042

search distinct in an up-to-date Stata for downloading the most recent version of that program.