new version of stdtable package available on SSC

[Maarten Buis]

Thanks to Kit Baum an update of the package, stdtable, is now available from SSC. It can be installed by typing in Stata ssc install stdtable. The biggest change is the way the replace option works. stdtable can overwrite the data with the table it creates by specifying the replace option. This can be useful for creating graphs, but the downside is that it overwrites the data. This new version allows the replace(frame_name) option, which will replace the data in the data frame frame_name. The regular replace option still works, and is the only one allowed for Stata versions less than 16 (as data frames were introduced in Stata 16).

stdtable standardizes a cross tabulation such that the marginal distributions (row and column totals) correspond to some pre-specified distribution, a technique that goes back to at least (Yule 1912). The purpose is to display the association that exists in the table nett of the marginal distributions. Consider the example below:

. use "http://www.maartenbuis.nl/software/mob.dta", clear
(mobility table from the USA collected in 1973)

. tab row col [fw=pop]

       Father's |                    Son's occupation
     occupation | upper non  lower non  upper man  lower man       farm |     Total
----------------+-------------------------------------------------------+----------
upper nonmanual |     1,414        521        302        643         40 |     2,920
lower nonmanual |       724        524        254        703         48 |     2,253
   upper manual |       798        648        856      1,676        108 |     4,086
   lower manual |       756        914        771      3,325        237 |     6,003
           farm |       409        357        441      1,611      1,832 |     4,650
----------------+-------------------------------------------------------+----------
          Total |     4,101      2,964      2,624      7,958      2,265 |    19,912

There are many more people that went from a farm to lower manual than the other way around. However, the number of people in agriculture strongly declined so sons had to leave the farm. Moreover, the number of people in lower manual occupations were on the increase, offering room for those sons that had to leave their farm. We may be interested in knowing if this asymmetry is completely explained by these changes in the marginal distribution, or if there is more to it.

. stdtable row col [fw=pop], format(%5.0f) cellwidth(9)

----------------------------------------------------------------------------------
Father's        |                         Son's occupation                        
occupation      | upper non  lower non  upper man  lower man       farm      Total
----------------+-----------------------------------------------------------------
upper nonmanual |        42         24         17         13          4        100
lower nonmanual |        27         30         18         18          6        100
   upper manual |        16         20         33         23          8        100
   lower manual |        11         21         22         34         12        100
           farm |         4          6          9         12         69        100
                |
          Total |       100        100        100        100        100        500
----------------------------------------------------------------------------------

These standardized counts can be interpreted as the row and column percentages that would occur if for both fathers and sons each occupation was equally likely. It appears that the apparent asymmetry was almost entirely due to changes in the marginal distributions. Also, it is now much clearer that farming is much more persistent over generations than the other occupations.

[Maarten Buis]

Thanks to Kit Baum a new version of stdtable is now available on SSC. The purpose of the stdtable command is discussed above. The main addition in this new version is that is that if it is run in Stata 17, it will leave behind a collection which the user can manipulate using the collect command or directly export using collect export.

[Martinо Cоmelli]

This is awesome! Thank you.