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  • Lagged time dummies, panel regression

    Hello all,

    I am trying to estimate a panel regression measuring the effect of different events on different stocks. My data set contains a list of 1384 listed companies with daily data of different controls between jun 2018 and dec 2019. I already created a dummy variable which is 1 if the date is an event date and 0 otherwise. My concern now is that the effect might fully unfold only at a later day, so I would like to measure the effect one day, two and three day after the event.

    My question would be how do I create dummies for those additional days to also capture that effect?

    A secondary question would be as the days are trading days so some dates are missing can I just estimate a panel regression from a dataset containing all the dates with the event dummies or do I need to tell stata first that those are trading dates, or do I even need to include all the other dates, meaning could I just use the event dates instead and delete the other dates?

    I would appreciate some guidance, thanks a lot

    Here are some information about my data and the panel estimation I have done so far

    Code:
     obs:       546,285                         
     vars:            13                          16 Mar 2020 19:17
     size:    41,517,660                         
    ---------------------------------------------------------------------------------------------------------------------------------------------------------
                  storage   display    value
    variable name   type    format     label      variable label
    ---------------------------------------------------------------------------------------------------------------------------------------------------------
    c_id            int     %10.0g                c_id
    day             float   %td                  
    grp_id          int     %10.0g                grp_id
    size            double  %10.0g                Total Asset Size
    oroa            double  %10.0g                Operating ROA
    abr             double  %10.0g                Daily Adjusted Abnormal Return
    pb              double  %10.0g                Price to Book
    roa             double  %10.0g                ROA
    sa              double  %10.0g                Sales to Total Assets
    lev             double  %10.0g                Total Debt to Total Assets
    vol             double  %10.0g                daily Stock Volatility
    typeofevent     str3    %9s                   Type of Event
    dum_1           byte    %8.0g                 typeofevent==EVT
    Code:
    eststo:xtreg abr dum_1 size oroa pb roa sa lev vol, fe
    
    Fixed-effects (within) regression               Number of obs     =    530,136
    Group variable: c_id                            Number of groups  =      1,379
    
    R-sq:                                           Obs per group:
         within  = 0.0001                                         min =        111
         between = 0.0069                                         avg =      384.4
         overall = 0.0001                                         max =        390
    
                                                    F(8,528749)       =       7.52
    corr(u_i, Xb)  = -0.3115                        Prob > F          =     0.0000
    
    ------------------------------------------------------------------------------
             abr |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
    -------------+----------------------------------------------------------------
           dum_1 |  -.0003579    .000113    -3.17   0.002    -.0005794   -.0001364
            size |  -1.78e-10   5.27e-10    -0.34   0.736    -1.21e-09    8.55e-10
            oroa |  -.0000411   .0000117    -3.51   0.000    -.0000641   -.0000181
              pb |  -9.58e-08   6.85e-07    -0.14   0.889    -1.44e-06    1.25e-06
             roa |   .0000283    .000011     2.56   0.010     6.66e-06      .00005
              sa |   .0017127    .000429     3.99   0.000     .0008718    .0025536
             lev |  -7.32e-08   4.84e-06    -0.02   0.988    -9.56e-06    9.42e-06
             vol |   .0000124   2.20e-06     5.61   0.000     8.04e-06    .0000167
           _cons |  -.0005924   .0001779    -3.33   0.001    -.0009411   -.0002437
    -------------+----------------------------------------------------------------
         sigma_u |  .00101958
         sigma_e |  .02081602
             rho |  .00239334   (fraction of variance due to u_i)
    ------------------------------------------------------------------------------
    F test that all u_i=0: F(1378, 528749) = 0.74                Prob > F = 1.0000
    Code:
        +-----------------------------------------------------------------------------------------------------------------------------------------+
            | c_id         day   grp_id        size        oroa          abr          pb         roa       sa        lev       vol   typeof~t   dum_1 |
            |-----------------------------------------------------------------------------------------------------------------------------------------|
         1. |    1   25jun2018     4010           .           .   -.01309818       .7045           .        .          .    17.445        no        0 |
         2. |    1   26jun2018     4010           .           .   -.00472636       .6986           .        .          .    17.432        no        0 |
         3. |    1   27jun2018     4010           .           .    -.0038682       .6905           .        .          .    17.455        no        0 |
         4. |    1   28jun2018     4010           .           .    .02043473       .7001           .        .          .    18.349        no        0 |
         5. |    1   29jun2018     4010           .           .   -.00893511       .6828           .        .          .    18.341        no        0 |
            |-----------------------------------------------------------------------------------------------------------------------------------------|
         6. |    1   02jul2018     4010     6091759      1.1272   -.01051936       .6636       .9105     .014    28.6393    19.516        EVT       1 |
         7. |    1   03jul2018     4010     6091759      1.1272     .0035916       .6678       .9105     .014    28.6393    19.848         No       0 |
         8. |    1   04jul2018     4010     6091759      1.1272    .00271767        .665       .9105     .014    28.6393    19.839         No       0 |
         9. |    1   05jul2018     4010     6091759      1.1272    .00105467       .6614       .9105     .014    28.6393    19.796         No       0 |
        10. |    1   06jul2018     4010     6091759      1.1272    .00845053       .6693       .9105     .014    28.6393    20.429         No       0 |
            |-----------------------------------------------------------------------------------------------------------------------------------------|
        11. |    1   09jul2018     4010     6091759      1.1272    .00719415       .6857       .9105     .014    28.6393    22.034         No       0 |
        12. |    1   10jul2018     4010     6091759      1.1272   -.00624704       .6836       .9105     .014    28.6393    21.918         No       0 |
        13. |    1   11jul2018     4010     6091759      1.1272   -.00747198         .67       .9105     .014    28.6393     21.99         No       0 |
        14. |    1   12jul2018     4010     6091759      1.1272    .00511515       .6836       .9105     .014    28.6393    22.737         No       0 |
        15. |    1   13jul2018     4010     6091759      1.1272   -.00675701       .6778       .9105     .014    28.6393    22.257         No       0 |
            |-----------------------------------------------------------------------------------------------------------------------------------------|
        16. |    1   16jul2018     4010     6091759      1.1272    -.0041779       .6721       .9105     .014    28.6393    22.045         No       0 |
        17. |    1   17jul2018     4010     6091759      1.1272    .00716007       .6743       .9105     .014    28.6393    22.132         No       0 |
        18. |    1   18jul2018     4010     6091759      1.1272    .01014313       .6793       .9105     .014    28.6393    22.309         No       0 |
        19. |    1   19jul2018     4010     6091759      1.1272    .00896441       .6828       .9105     .014    28.6393    22.255         No       0 |
        20. |    1   20jul2018     4010     6091759      1.1272    .01805844        .705       .9105     .014    28.6393     24.13         No       0 |
            |-----------------------------------------------------------------------------------------------------------------------------------------|
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