How to tell which dummy is for which region if I create region dummies using i.region?

[Linghui Han]

My code goes like this: reg occ wage i.region

[Rich Goldstein]

this would be easier to answer if you followed the advice in the FAQ and showed the results within CODE blocks (see the FAQ); you can make things easier on yourself by (1) ensuring that you label the categories and (2) using the allbase option

[William Lisowski]

Enlarging on Rich's answer, the code below demonstrates a meaningless regression of automobile price on one continuous variable - weight - and two categorical variables - foreign, which has value labels "Domestic" and "Foreign" - and rep78, which has no value labels. In the regression output you can see that foreign shows the labels and rep78 shows the values.

. sysuse auto, clear
(1978 Automobile Data)

. codebook foreign rep78

-----------------------------------------------------------------------------------------------
foreign                                                                                Car type
-----------------------------------------------------------------------------------------------

                  type:  numeric (byte)
                 label:  origin

                 range:  [0,1]                        units:  1
         unique values:  2                        missing .:  0/74

            tabulation:  Freq.   Numeric  Label
                            52         0  Domestic
                            22         1  Foreign

-----------------------------------------------------------------------------------------------
rep78                                                                        Repair Record 1978
-----------------------------------------------------------------------------------------------

                  type:  numeric (int)

                 range:  [1,5]                        units:  1
         unique values:  5                        missing .:  5/74

            tabulation:  Freq.  Value
                             2  1
                             8  2
                            30  3
                            18  4
                            11  5
                             5  .

. regress price weight i.foreign i.rep78, allbase

      Source |       SS           df       MS      Number of obs   =        69
-------------+----------------------------------   F(6, 62)        =     10.38
       Model |   288985161         6  48164193.5   Prob > F        =    0.0000
    Residual |   287811798        62  4642125.77   R-squared       =    0.5010
-------------+----------------------------------   Adj R-squared   =    0.4527
       Total |   576796959        68  8482308.22   Root MSE        =    2154.6

------------------------------------------------------------------------------
       price |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
      weight |   3.392021    .436278     7.77   0.000     2.519914    4.264128
             |
     foreign |
   Domestic  |          0  (base)
    Foreign  |   3530.574   852.8057     4.14   0.000     1825.839    5235.308
             |
       rep78 |
          1  |          0  (base)
          2  |   542.3997   1706.922     0.32   0.752     -2869.69    3954.489
          3  |   836.6638   1580.637     0.53   0.598    -2322.985    3996.312
          4  |    521.878   1650.986     0.32   0.753    -2778.396    3822.152
          5  |   1096.374   1759.422     0.62   0.535    -2420.661    4613.409
             |
       _cons |  -5950.765   2037.208    -2.92   0.005    -10023.09   -1878.444
------------------------------------------------------------------------------

[Linghui Han]

Thank both of you very much!

[Nae Khar]

Building off on this question, is it possible to ask stata to exclude a different category in i.region or i.rep78? For example, how would I exclude i.rep78 #2 and use that as a base, instead of its current default which excludes i.rep78 #1?

[Nae Khar]

For anyone who faces the same issue, its: regress price weight i.foreign ib2.rep78