Stata dropping first year from panel dataset

[Harmeet Sehgal]

Hello,

I am using Stata 19 SE.

I have a panel dataset from 2015-2024 with one DV, 3 IVs and 7 CVs. I am running an OLS regression with year and industry fixed effects. But when I run the regression I can only see results form 2016-2024 - im not sure where my data from 2015 has gone. I haven't lagged any variables.

I would appreciate any help.

Thank you,
Harmeet

[Stephen Jenkins]

Show us the results of the -xtset- for your panel -- it might be informative. (Given the little information you provide, it's hard to be more helpful.)

[Harmeet Sehgal]

xtset id year, yearly

Panel variable: id (strongly balanced)
Time variable: year, 2015 to 2024
Delta: 1 year

I then used the command:
regress esgc b_indep bgd bsize leverage roa liquidity ceoduality bmf bt ln_fs i.year i.industrycode, vce(robust)

[Devra Golbe]

Can you explain what you mean by "only see[ing] results form 2016-2024?" Does the number of observations used in your regression differ from the number in the whole sample, including 2015? Have you used e(sample) to verify that the missing observations come from 2015? Or are you missing a coefficient for the 2015 dummy? Stata typically omits the first category from the output.

[Daniel Schaefer]

Seems like 2015 is the reference category for your i.year variable.

[Harmeet Sehgal]

These are my (e)sample results.
year | Freq. Percent Cum.
------------+-----------------------------------
2015 | 135 8.30 8.30
2016 | 139 8.54 16.84
2017 | 142 8.73 25.57
2018 | 149 9.16 34.73
2019 | 159 9.77 44.50
2020 | 168 10.33 54.82
2021 | 182 11.19 66.01
2022 | 186 11.43 77.44
2023 | 185 11.37 88.81
2024 | 182 11.19 100.00
------------+-----------------------------------
Total | 1,627 100.00



When I run my regression (below) the part of the regression results that is by year, there is only 2016-2024.

Linear regression Number of obs = 1,627
F(29, 1597) = 17.76
Prob > F = 0.0000
R-squared = 0.3241
Root MSE = 21.26

------------------------------------------------------------------------------
| Robust
esgcs | Coefficient std. err. t P>|t| [95% conf. interval]
-------------+----------------------------------------------------------------
b_indep | -.0366825 .043487 -0.84 0.399 -.1219802 .0486152
bgd | -.0169863 .057001 -0.30 0.766 -.128791 .0948184
bsize | .6369739 .3178877 2.00 0.045 .0134529 1.260495
leverage | .0634554 .0350305 1.81 0.070 -.0052552 .1321659
roa | -20.36302 6.071272 -3.35 0.001 -32.27152 -8.454516
liquidity | .4739907 .4346322 1.09 0.276 -.3785188 1.3265
ceoduality | -3.685138 1.928008 -1.91 0.056 -7.46683 .0965534
bmf | -.8864662 .2217089 -4.00 0.000 -1.321337 -.4515952
bt | .0289759 .2601261 0.11 0.911 -.4812486 .5392003
ln_fs | -8.414731 .5659114 -14.87 0.000 -9.524738 -7.304723
|
year |
2016 | .1727795 2.455818 0.07 0.944 -4.644185 4.989744
2017 | .4437581 2.495395 0.18 0.859 -4.450835 5.338351
2018 | 1.67385 2.447305 0.68 0.494 -3.126418 6.474117
2019 | -.8569423 2.528297 -0.34 0.735 -5.816072 4.102188
2020 | -1.237642 2.572449 -0.48 0.631 -6.283374 3.80809
2021 | .9449458 2.481083 0.38 0.703 -3.921576 5.811468
2022 | -.5474989 2.55903 -0.21 0.831 -5.56691 4.471912
2023 | -.9306513 2.644163 -0.35 0.725 -6.117046 4.255743
2024 | -8.252582 2.814483 -2.93 0.003 -13.77305 -2.732112
|
industrycode |
15 | -16.48295 4.563881 -3.61 0.000 -25.43478 -7.531127
20 | -1.775139 2.760052 -0.64 0.520 -7.188846 3.638567
30 | 24.15412 2.706654 8.92 0.000 18.84516 29.46309
35 | 7.210148 1.80629 3.99 0.000 3.667199 10.7531
40 | -1.949735 1.708239 -1.14 0.254 -5.30036 1.400891
45 | -6.309971 2.432422 -2.59 0.010 -11.08105 -1.538895
50 | -1.813302 1.642618 -1.10 0.270 -5.035216 1.408612
55 | -7.278477 2.813872 -2.59 0.010 -12.79775 -1.759207
60 | -15.2268 4.181579 -3.64 0.000 -23.42876 -7.024844
65 | -.9028132 3.528564 -0.26 0.798 -7.823917 6.018291
|
_cons | 279.7961 10.81416 25.87 0.000 258.5847 301.0076
------------------------------------------------------------------------------

[Devra Golbe]

Your posted results are difficult to read, because you have not followed the advice in the FAQs (12.3) to use CODE delimiters for your code and output. That said, as Daniel and I proposed, the output indicates that 2015 is your omitted year category. If you check your industry variable I bet you will see that a reference category has been omitted there as well.

[Harmeet Sehgal]

oh okay thank you very much